Clear tools, explained

Interactive car loan studio with extra-payment what-ifs, amortization preview, and PDF export. See months and interest saved instantly—no sign-up.

Compare two personal loan offers on payment and total cost, then stress-test extra payments. Export a PDF summary from your browser.

Student loan payoff studio with live extra-payment savings, balance chart, amortization preview, and downloadable plan summary.

Compare credit card minimum-only vs minimum+extra vs fixed payments. See the interest trap clearly and export your payoff plan.

Build a multi-debt payoff plan that clears smallest balances first. Compare snowball vs avalanche, tweak extra payments, and see interest vs motivation trade-offs instantly.

Attack highest-APR balances first with a multi-debt simulator. Compare avalanche vs snowball, adjust extra payments live, and see interest savings versus motivational wins.

Refinance decision studio: current vs new payments, lifetime savings, and break-even timing with PDF export—all client-side.

Home equity loan studio with available equity gauge, payment and interest estimates, amortization preview, and PDF summary.

Compare monthly vs bi-weekly vs extra-monthly mortgage strategies. See interest and months saved, then download a summary.

Balloon loan studio showing amortizing payment, interest before the lump sum, and the balloon due—with schedule preview and PDF export.

Calculate principal and interest on a fixed-rate mortgage. Instantly see how price, down payment, rate, and term shape your payment.

Compare the long-term cost of renting versus buying a home. Factor appreciation, opportunity cost, and ownership expenses.

Estimate how much house you can afford from income, debts, and down payment. Stay within healthy housing-cost guidelines.

Estimate annual and monthly property taxes from assessed value and local millage. Budget ownership costs more accurately.

Project monthly and annual cash flow for a rental property. Account for rent, vacancy, expenses, and financing.

Compute capitalization rate from NOI and property value. Compare income properties on a standardized yield basis.

Calculate GRM to screen rental properties quickly. Compare price relative to gross rental income.

Estimate return on investment for renovations and upgrades. Weigh project cost against expected value added.

Project how long it will take to save for a home down payment. Factor current savings, monthly deposits, and interest.

Estimate land transfer taxes and typical closing costs at purchase. Budget cash-to-close beyond the down payment.

Estimate cleaning fees per turnover from labor hours, hourly rate, supplies, and laundry.

Split monthly rent proportionally by bedroom square footage for a fairer roommate share.

Split rent by room size, then add a master-bedroom premium for en-suite or larger space.

Project investment growth with compound interest, regular contributions, and a coasting phase with zero new deposits. Visualize how time and rate multiply wealth after you stop contributing.

Estimate when you can reach financial independence using savings rate and withdrawal assumptions. Plan your FIRE number with clarity.

Calculate how much you need to retire based on income replacement. Translate lifestyle goals into a portfolio target.

Project tax-advantaged retirement account growth with contributions and employer match. See the long-term power of deferred compounding.

Model dividend growth with reinvestment (DRIP). Estimate how yield and compounding expand share ownership over time.

See how inflation erodes the real value of money over time. Convert today’s dollars into future purchasing power.

Calculate net worth by subtracting liabilities from assets. Establish a clear baseline for wealth-building progress.

Estimate how long an investment takes to double using the Rule of 72. Quickly compare rates of return.

Simulate dollar-cost averaging with fixed contributions over time. Estimate shares accumulated and average cost basis.

Quantify how advisory and fund fees erode long-term returns. Compare low-fee versus high-fee portfolio outcomes.

FIRE calculator with rental property: model salary, side income, expense inflation, investment returns, rental acquisitions, and net worth milestones to your financial independence date.

Emergency fund planner with a life-shock simulator: job loss, medical bill, rent hike, or partner income gone.

Multi-goal savings timeline with a sequential vs split funding optimizer that recommends the fastest path to hit all deadlines.

Plug in your age, savings, monthly investing, and the income you actually want later. The date that comes back is the first year the 4% rule (or your own withdrawal rate) covers that income—not a promise from a brochure.

You already have a pile of cash or investments and a yearly spend. This walks that balance forward, growing it at your assumed return and raising spend with inflation, until the account hits zero.

A straight-line look at invested savings by your 40th birthday. It ignores promotions, kids, and house purchases on purpose so you can see the path if nothing else changes.

A checkpoint at 50: current invested savings, the monthly amount you can still send, and a return you would accept. Peak-earnings years and college bills sit in this window, so run it twice—full deposits and a gap.

A million dollars is a round number, not a personality. This finds the month your invested pile plus deposits hits $1,000,000 at the return you assume.

Start from the yearly spend you could live on, pick a withdrawal rate, and get the pile you need on day one of retirement. No age, no salary story—just the target.

Same engine as “When can I retire?” with the question phrased the way people say it at dinner. The age is when invested savings can cover the income you type.

A checkpoint many people use because 60 is close enough to feel real and far enough to still change deposits. Investments only unless you add other assets yourself.

Twenty years of $1,000 a month is $240,000 of your own cash. The rest is whatever the market did. This splits those two so the “interest” is not a mystery lump.

You already picked a retirement age. This counts the years and months from today, then shows whether your current savings rate is on track for the nest egg that age implies.

Birthday to today, in days. No astrology, no “life path number.” Leap days are included because they happened.

Pick the birthday you are walking toward. If that age already passed, it says so instead of inventing a future date.

A rough count of Saturdays-and-Sundays between now and your 80th birthday. It is meant to make a weekend feel spendable, not to predict your health.

Days alive times the hours you think you actually sleep, not the eight hours a poster recommended. Night-shift and new parents should type the honest number.

Paid hours versus days you have been alive. Commute is separate on another page. Unpaid care work is not in this number unless you add those hours yourself.

Screen time for the years you have already lived, plus a projection if the daily habit stays put until a life expectancy you choose. Your phone’s weekly report is a better input than a guess.

Workdays times years on that commute, plus a simple hour total. Remote days should come out of the workweek you type.

Career start to an end age you choose—retirement, a planned exit, or “I have no idea, try 67.” It is elapsed years, not vesting years.

Age versus a life-expectancy number you type. Averages hide illness and luck. Use a table from your country’s stats office if you want a less made-up expectancy.

Current age divided by the expectancy you assume. Halfway is not a moral event. It is just 50%.

$100 is small enough that people dismiss it. Twenty or thirty years later it is not small. This is the same compounding math as the $1,000 page with a humbler default.

A ten-year future value for money you already have, with an optional monthly add. Ten years is long enough for compounding to show and short enough to remember the assumption.

What a pile of cash buys after N years if prices rise at the rate you type. It is not “lost” from the bank. It is lost at the grocery store.

Monthly extras plus the quiet annual bills (insurance, trips, subscriptions you forgot). The yearly total is what a raise has to beat after tax.

Payment is the loud number. Insurance, fuel, maintenance, parking, and a simple depreciation guess are the rest. Add them and you get a monthly cost you can compare to a transit pass.

Drinks per week times price, stretched across the years you expect to keep the habit. It is not an argument for quitting coffee. It is the receipt.

Ten dollars is a takeout lunch or two delivery fees. Invested on a boring schedule it stops being a joke. This assumes you actually send the money somewhere that earns the rate you type.

A counterfactual, not a time machine. It shows the pile you would have if the monthly amount and average return you type had run for the last decade. Real markets were lumpier.

The first hundred thousand is mostly deposits. After that, growth does more of the lifting. This solves for the month you cross $100,000.

Backs into the yearly income that supports a savings rate big enough to hit $1,000,000 in the years you have left, given what you already invested. It assumes you can save a percent of salary, not that you spend nothing.

The day you met—not the day you made it official. Type that date and get years, months, and days. Arguments about “when it counted” are not the calculator’s job.

Anniversary date to today. Useful for a card, a fight about “how long has it been,” or a 500-day dinner you would otherwise miss.

Days together divided by days you have been alive. High school sweethearts get a bigger percent than people who met at 34. Neither is a score.

1,000 days is about 2 years and 9 months. If you already passed it, the page says how long ago instead of inventing a future party.

Not photos, not a scientific count. You pick how many shared “events” you think happen in a typical week—meals that were not leftovers, trips, fights you still tell, concerts. The page multiplies that by time together.

Calculate net crypto profit or loss and ROI after buy and sell trading fees. Model break-even sell price before you exit a position.

Project dollar-cost averaging returns for Bitcoin, Ethereum, or any token. Estimate tokens accumulated, average cost, and ROI under a growth assumption.

Calculate cryptocurrency market capitalization from circulating supply and price. Optionally infer total market size from a dominance share.

Calculate fully diluted valuation (FDV) from max supply and price. Compare FDV to circulating market cap and unlocked supply percentage.

Reverse-engineer implied token price from a target market cap or FDV and a supply base. Useful for launch pricing and scenario planning.

Project token circulating supply over time with TGE unlocks, cliff vesting, linear vesting, and monthly emissions.

Compute constant-product (x·y=k) pool metrics: spot price, LP share for a deposit, swap output, and price impact.

Estimate compounding staking rewards with daily, weekly, monthly, or yearly compounding. Compare ending balances across intervals.

Measure percentage return and annualized CAGR for any crypto investment over years and days held.

Estimate upfront token launch costs across blockchain deploy, smart contracts, liquidity, audits, marketing, and legal contingency.

Convert income goals into a sustainable freelance hourly rate. Account for taxes, expenses, and non-billable time.

Estimate net take-home pay after taxes and deductions. Translate gross salary into spendable monthly income.

Estimate Social Security and Medicare self-employment taxes. Prepare for quarterly obligations with clearer numbers.

Convert annual salary into hourly, daily, and weekly equivalents. Benchmark offers and freelance rates fairly.

Calculate overtime earnings from base hourly rate and extra hours. Estimate weekly pay with time-and-a-half premiums.

Compute new salary and raise percentage from current and offered pay. Negotiate with clear before-and-after figures.

Estimate total earnings from base pay plus sales commissions. Model quota attainment and variable income.

Measure side hustle profitability after expenses and taxes. Know whether extra work is truly worth your time.

Convert tracked billable hours into revenue at your rate. Monitor utilization and monthly billing projections.

Adjust salary expectations when relocating between cities. Compare purchasing power across cost-of-living indexes.

Freelance true-rate planner with a fee waterfall (platform → processor → FX → tax → non-billable) and reverse invoice math.

See your effective hourly rate after marketplace or platform percentage fees.

Estimate warehouse weekly pay from regular hours, overtime hours, and time-and-a-half (or custom) premiums.

Estimate shift premium pay from base hourly rate and a differential percentage or flat add-on.

Estimate gross pay for a 12-hour shift with optional differential percent or flat add-on.

Calculate how large your emergency fund should be. Base the target on monthly expenses and desired coverage months.

Find the monthly savings needed to hit a goal by a deadline. Stay on track for vacations, purchases, or milestones.

Reveal the long-term cost of small daily purchases. See how tiny habits compound into annual and multi-year spending.

Split restaurant bills fairly with custom tip percentages. Get per-person totals in seconds.

Calculate final sale prices after percentage discounts. Instantly see savings before you checkout.

Compare two products by price per unit to find true value. Spot which package size is actually cheaper.

Estimate fuel cost for a trip from distance, MPG, and gas price. Budget road travel with fewer surprises.

Add up streaming, software, and membership subscriptions. Reveal hidden monthly and yearly recurring spend.

Compute simple interest on a principal over time. Ideal for basic loans, notes, and classroom finance math.

Calculate percentage change between two values instantly. Useful for prices, metrics, and performance tracking.

Track income and expenses in your browser with localStorage persistence. Log transactions, filter your ledger, and watch balance, income, and spending update live.

Wedding budget line-item planner with a deposit milestone cashflow calendar against your savings balance.

Baby first-year cost planner with a parental leave income bridge into childcare start — finds the tightest cash month.

Subscription and fixed-cost audit with a runway extension meter — pause items and see months of emergency runway gained.

Estimate the electricity and water cost of a single washer load from kWh, rates, and water use.

Estimate electricity cost for a dryer cycle from kWh per load and your utility rate.

Estimate annual electricity cost to run a refrigerator from yearly kWh and your utility rate.

Estimate monthly dog food spend from bag price, bag size, and daily feeding amount.

Estimate electricity cost for a remote workday from device wattage, hours, and utility rate.

Divide a grocery trip (or weekly food budget) by the number of meals it covers to get cost per meal.

Divide grocery and packaging costs by the number of meal-prep portions to get cost per meal.

Set a meal prep sell price from batch cost, portions, and target margin.

Divide a recipe’s ingredient batch cost by the number of servings for cost per plate.

Estimate beverage cost per cup from beans, milk, cup, and lid costs.

Calculate your cumulative GPA from credit hours and grade points. Track academic progress across multiple terms.

Find the final exam score required to hit your target course grade. Plan study effort with a clear number.

Compute a weighted course average from category scores. Handle homework, quizzes, midterms, and projects fairly.

Estimate percentile standing from SAT or ACT composite scores. Contextualize results against peer performance.

Project multi-year college costs with tuition inflation. Plan savings and aid gaps before enrollment.

Build a student loan amortization estimate with payment and interest totals. Understand repayment before you borrow.

Allocate weekly study hours across courses by credit load and difficulty. Build a realistic study schedule.

Estimate reading time from word count and reading speed. Plan assignments and research sessions accurately.

Convert page counts to estimated word counts using spacing and font assumptions. Scope essays and reports faster.

Measure scholarship return against application time invested. Prioritize awards with the best payoff.

Estimate AP exam composite conversion to a 1–5 score. Gauge readiness before test day.

Convert class rank and class size into percentile standing. Understand relative academic position quickly.

Convert between letter grades and percentage ranges. Standardize transcripts and syllabus comparisons.

Convert correct answers into quiz percentages and letter estimates. Grade practice tests in seconds.

Estimate annual homeschool costs across curriculum, activities, and supplies. Plan education spending with clarity.

Budget dorm setup and monthly living extras beyond tuition. Avoid surprise first-year housing costs.

Estimate textbook resale value and net cost of ownership. Decide whether to buy new, used, or rent.

Project graduate school loan payoff timelines with optional extra payments. Plan repayment before you enroll.

Estimate weeks needed to finish an online course at your weekly study pace. Stay accountable to launch dates.

Calculate attendance percentage from classes attended versus scheduled. Monitor course participation requirements.

Advanced online scientific calculator with trigonometry, logarithms, exponents, roots, factorial, memory keys, degree/radian modes, and session history.

Compute population or sample variance and standard deviation from summary stats. Quantify data spread quickly.

Estimate required sample size for a proportion survey at a chosen confidence level. Design studies with adequate power basics.

Build a mean confidence interval from sample mean, SD, and n. Report estimates with statistical context.

Convert a raw score into a z-score and approximate two-tailed p-value. Standardize results for comparison.

Calculate P(n, r) and C(n, r) for counting problems. Solve ordering and selection scenarios instantly.

Solve right-triangle sides with a² + b² = c². Find hypotenuse or a missing leg instantly.

Solve ax² + bx + c = 0 for real roots. Inspect discriminant and root values instantly.

Multiply two 2×2 matrices and view the resulting matrix entries. Practice linear algebra fundamentals quickly.

Convert a fraction numerator/denominator into decimal and percent forms. Simplify homework checks instantly.

Find the greatest common divisor and least common multiple of two integers. Essential for fractions and scheduling math.

Evaluate exponential growth and corresponding log time-to-target. Model compounding quantities with clarity.

Compute nth terms and sums for arithmetic or geometric sequences. Solve progression problems quickly.

Calculate AND/OR probabilities for independent events. Combine event likelihoods with correct probability rules.

Derive mean estimates from count, sum, min, and max summaries. Summarize datasets with core descriptive metrics.

Estimate survey margin of error from sample size and confidence z-score. Communicate poll precision clearly.

Compute a one-sample z test statistic from mean hypotheses. Compare evidence against a null value.

Estimate Pearson correlation from summarized covariance inputs. Gauge linear association strength quickly.

Compute n! and base^exponent for common math tasks. Handle counting and power calculations quickly.

Calculate interior angle sums and regular polygon area from sides and side length. Solve geometry problems faster.

Compute circumference and area from radius or diameter. Cover essential circle formulas in one place.

Estimate severance packages from salary and weeks offered. Plan finances during a job transition.

Calculate paid time off accrued from hours worked and accrual rates. Track leave balances accurately.

Estimate remaining FMLA leave from entitlement and days already used. Track protected leave availability.

Estimate temporary disability weekly benefits from wage replacement percentage. Rough-plan injury income support.

Calculate employee turnover rate for a period from separations and average headcount. Monitor retention health.

Estimate employer payroll tax burden from wages and combined tax rates. Budget fully loaded labor costs.

Compare total cost of a W2 hire versus a contractor rate. Make staffing model decisions with clearer math.

Estimate settlement value from remaining restricted months and monthly pay. Frame negotiation ranges for covenants.

Estimate wage-loss damages from lost pay over a claim period. Support early case valuation discussions.

Check how a salary compares with an overtime exemption threshold. Flag potential nonexempt risk quickly.

Compute OSHA incidence rates from recordable cases and hours worked. Benchmark workplace safety performance.

Score candidates with weighted hiring criteria. Standardize interview evaluations across a hiring panel.

Calculate employee Net Promoter Score from promoters, passives, and detractors. Measure workplace advocacy.

Measure recruiting cost per hire from internal and external spend. Optimize hiring budget efficiency.

Calculate average days to fill open roles from total days open and hire count. Track recruiting speed.

Estimate return on training investment from program cost and performance gains. Justify L&D spend with numbers.

Calculate performance bonuses from target bonus and attainment percentage. Communicate variable pay clearly.

Total relocation reimbursement from moving, housing, and travel allowances. Clarify package value before a move.

Calculate trip per diem totals from daily rates and travel days. Simplify business travel allowances.

Estimate vested pension value from account balance and vesting percentage. Understand retirement benefit ownership.

India CTC to in-hand salary calculator: break down basic, HRA, special allowance, employee PF, FY 2025-26 tax under new or old regime, and compare negotiation scenarios before you accept an offer.

Calculate bootstrapped SaaS net burn and runway from cash, revenue, and opex. Instant, free, no sign up.

Price a 1-hour engineering meeting from loaded salaries and headcount. Free online tool, instant, no email.

Compare AI support agent cost vs human tickets deflected. Instant ROI formula, free, no sign up.

Compare 1099 contractor rate vs W2 loaded cost (taxes, benefits, PTO). Free, instant, no sign up.

Break down recruiter fees, ads, interview time, and tools to hire a developer. Free online calculator.

Estimate turnover cost to replace a software engineer: hiring, ramp, and lost output. Free, instant.

Prorate annual PTO into each pay period for mid-year hires. Free online tool, instant, no sign up.

Calculate time-and-a-half overtime from hourly rate and weekly hours over 40. Free, instant, no email.

Estimate restaurant weekly labor from shifts, wage, and headcount. Free online estimator, no sign up.

Set a solo developer minimum hourly rate from salary target, utilization, and costs. Free formula tool.

Estimate BC private-sale used-car PST from price vs Black Book. 2026 luxury tiers, free, instant.

Estimate 2026 BC property transfer tax with first-time home buyer exemption. Free, instant, no sign up.

Calculate BC statutory holiday pay from average day’s pay. Free online formula, instant, no email.

Estimate British Columbia statutory holiday pay from average daily wages or an hourly rate and hours.

Estimate PayPal fees on domestic and international sales. See net proceeds after percentage and fixed fees.

Calculate selling price from cost and markup percentage. See profit per unit and implied margin.

Estimate monthly FBA-style storage fees from box dimensions, quantity, and a cubic-foot rate.

Size MT4 USD/JPY lots from account risk %, stop pips, and balance. Free, instant, no sign up.

Turn picker lines per hour into labor cost per line and per shift. Free online calculator, no sign up.

Find faceless YouTube automation break-even views from RPM and monthly costs. Free, instant.

Get true dropshipping break-even ROAS after COGS, ads, and fees. Free margin calculator, no sign up.

Compare preventative maintenance cost vs downtime loss on facility equipment. Free, instant, no email.

Price a house cleaning job from hours, hourly rate, supplies, travel, and target margin.

Estimate total fuel cost for a road trip from miles, MPG, and gas price. Budget driving vacations accurately.

Calculate EV charging cost from battery size, charge amount, and electricity rates. Compare home vs public charging.

Compare multi-year lease payments against buying and ownership costs. Decide with clearer long-term math.

Estimate vehicle value after years of depreciation. Forecast ownership equity and replacement timing.

Calculate monthly and annual toll spend for a commute. Weigh express-lane costs against time savings.

Compare two auto insurance quotes by premium and deductible tradeoffs. Identify the lower expected annual cost.

Estimate flight CO₂ emissions from distance and passengers. Understand travel climate impact roughly.

Budget hotel stays including nightly rate, taxes, and fees. Avoid surprise lodging totals at checkout.

Convert vacation budgets between home and destination currencies. Plan spending before you travel abroad.

Estimate airline baggage fees for checked bags across travelers. Prevent packing surprises at the counter.

Estimate speeding fines from base penalty plus per-mph overage. Understand potential ticket costs.

Estimate drive time and fuel use between distance and average speed. Plan multi-stop driving days.

Estimate parking garage totals from hourly rates, daily caps, and duration. Budget urban parking accurately.

Check tow capacity headroom from vehicle rating and trailer weight. Tow more safely with clearer margins.

Estimate motorcycle loan payments from price, rate, and term. Plan financing before you buy.

Estimate annual boat maintenance from value-based percentages and slip fees. Budget ownership beyond the purchase.

Estimate rideshare net earnings after platform fees, fuel, and expenses. Know your true hourly take-home.

Compare monthly transit passes against pay-per-ride costs. See whether a pass actually saves money.

Estimate total car rental cost including daily rate, taxes, and extras. Budget rental cars without fee surprises.

Estimate jet lag recovery days from time zones crossed. Plan arrival buffers for important trips.

Estimate British Columbia PST on a private-sale used vehicle using the higher of purchase price or Canadian Black Book wholesale value, including 2026 luxury tiers and zero-emission exemption.

Three-way car TCO planner: keep current vs lease vs buy — year-by-year matrix highlighting the cheapest option.

Estimate the fuel (and optional wear) cost of a round-trip car commute for a single workday.

Estimate winter EV charging cost with a cold-weather efficiency penalty on kWh used.

Estimate fuel burned (and cost) while a vehicle idles from minutes, GPH, and gas price.

Estimate fuel burned waiting in drive-thru lines from minutes, idle GPH, and gas price.

Estimate BMR, TDEE, daily calorie targets, and macro splits from your age, sex, weight, height, activity level, and goal adjustment.

Scale recipe ingredient quantities up or down by serving size. Adapt any recipe without guesswork.

Convert batter volume between baking pan areas. Move recipes across pan sizes with better confidence.

Calculate coffee dose and water from brew ratios. Dial in pour-over and batch brew strength.

Estimate roasting time from weight and minutes-per-pound guidance. Plan oven schedules with fewer surprises.

Relate shutter speed, aperture, and ISO to exposure value. Balance photo exposure settings faster.

Estimate hyperfocal distance from focal length, aperture, and circle of confusion. Maximize landscape sharpness.

Calculate time-lapse shooting intervals from event duration and clip length. Plan smoother sequences.

Camera-card planner: how many gigabytes a shoot eats at your record bitrate, including audio. Use this before you buy cards—not the encode-for-YouTube bitrate tool.

Convert sound frequency to wavelength in air. Useful for room treatment and speaker placement intuition.

Estimate lumens needed from room area and foot-candle targets. Plan brighter, more usable spaces.

Estimate watering frequency from soil dry-down days and climate multipliers. Build a practical plant care cadence.

Calculate aquarium gallons from length, width, and height. Size filters and stocking with better accuracy.

Estimate paint gallons needed from wall area, coats, and coverage rating. Buy the right amount before painting day.

Estimate wallpaper rolls from wall area and roll coverage. Reduce leftover waste and mid-project shortages.

Calculate flooring material needed with waste allowance. Order planks or tile with fewer shortages.

Estimate moving truck size from rooms and box counts. Plan move day capacity with less stress.

Allocate a holiday gift budget across recipients evenly or with priorities. Stay festive without overspending.

Estimate tables needed from guest count and seats per table. Plan reception layouts quickly.

Estimate daily pet food portions from weight and calories per cup. Support healthier feeding routines.

Estimate CO2 injection rate targets from tank volume and drop-checker goals. Support planted tank stability.

Pre-filled $25,000 vehicle affordability check using the 20/4/10 auto rule.

Pre-filled $500,000 home purchase check using 28/36 debt-to-income guidelines.

Pre-filled $30,000 wedding cost check with cash cushion and savings timeline.

Pre-filled flagship phone purchase (~$1,200) with emergency-fund protection check.

Pre-filled ~$55/mo gym membership check against the 50/30/20 wants slice.

Blank-canvas affordability engine for custom one-time or recurring targets.

Calculate adult BMI from height and weight with WHO category bands.

Estimate a child's BMI percentile from age, sex, height, and weight.

Estimate body fat % with neck, waist, hip, and height tape measurements.

Check body fat against approximate Army tape-test screening limits.

Compare Hamwi, Devine, Robinson, and Miller ideal weight formulas.

Split scale weight into lean mass and fat mass from body-fat %.

Measure waist-to-hip ratio and common health-risk screening bands.

Flag central adiposity risk with a simple waist ÷ height check.

Calculate fat-free mass index and normalized FFMI for lifters.

Compute Body Roundness Index from height and waist circumference.

Estimate basal metabolic rate (calories at rest) with Mifflin–St Jeor.

Find total daily energy expenditure from BMR and activity level.

Turn a weekly fat-loss goal into a daily calorie deficit and target.

Estimate weeks to reach a goal weight at a chosen weekly loss rate.

Set daily protein grams from body weight and training goal.

Estimate calories burned using MET values for activity and duration.

Convert daily steps into estimated calories using stride and weight.

Calculate a daily surplus and timeline to gain weight at a chosen rate.

Find fat-burn, aerobic, and peak zones from age and resting heart rate.

Estimate max heart rate from age using common population formulas.

Estimate 1RM from a submaximal set using Brzycki, Epley, and Lander.

Convert distance and time into pace, speed, and 5K projections.

Estimate VO₂ max from a 12-minute Cooper test distance.

Estimate walking calories from distance, speed, and body weight.

Estimate bike-ride calories from distance, speed, and weight.

Estimate resistance-training calories from duration and intensity.

Estimate due date and gestational age from days since last period (LMP).

Back-calculate an estimated conception window from cycle timing.

Predict ovulation day and fertile window from cycle length and LMP.

Project your next period from last start date and average cycle length.

Convert days since LMP into pregnancy week and trimester.

See IOM-style total gain ranges from pre-pregnancy BMI.

Estimate IVF due date from embryo transfer day and embryo age.

Estimate extra daily calories while breastfeeding.

Estimate daily water needs from weight, exercise, and climate.

Pick bedtime or wake time aligned to 90-minute sleep cycles.

See remaining caffeine over time from dose and half-life.

Estimate blood alcohol content from drinks, weight, and time (Widmark).

Set 16:8, 18:6, or custom fast/eat windows from wake time.

Estimate fluid to replace from workout duration and intensity.

Add up caffeine milligrams from coffee, tea, and energy drinks.

Compare hours slept vs need to estimate weekly sleep debt.

Divide monthly dues and fees by workouts you actually attend.

Compare tubs by price, servings, and grams of protein per scoop.

Tally pills and powders into a realistic monthly supplement budget.

Estimate PT costs from sessions, copay, and deductible.

Compare first-year cost of glasses versus contacts.

Compare home equipment and apps vs gym dues over 12 months.

Bulk and cut macro calculator for lifters: set lean bulk or cutting calories from TDEE, weekly rate, and training experience—with protein-forward macros and training-day carb cycling.

Reverse diet planner with adaptive weekly calorie bumps — smaller increases when the scale is still dropping too fast.

Body recomposition planner with a training-volume deficit cap — more hard sets means a smaller deficit and higher protein.

Calculate epoxy volume for river tables from length, width, depth, and coat count.

Compute fragrance load in ounces from wax weight and fragrance percentage.

Estimate NaOH and water for cold-process soap from oil weight and superfat.

Convert yardage when swapping yarn gauge in a knitting pattern.

Estimate backing and binding fabric yardage for a quilt size.

Estimate starting chain count from blanket width and stitch width.

Price HTV/vinyl crafts with material, labor, and margin.

Calculate resin material cost per coaster for small batch pours.

Estimate usable hide area and how many bag patterns fit.

Compute water, starter, and discard from flour and hydration %.

Plan basking vs cool zones for a bearded dragon enclosure.

Estimate CO₂ bubble rate from tank size and plant load.

Split daily raw portions into meat, bone, organ, and veg.

Estimate winter hay bales from horses, daily intake, and season length.

Size nesting boxes and coop floor space for a flock.

Estimate chiller BTU load for axolotl tank temperature control.

Size pond pump GPH from volume and desired turnover hours.

Estimate daily vitamin C mg from guinea pig body weight.

Model dubia colony startup, monthly cost, and sales ROI.

Budget monthly litter spend by cat count and bag price.

Compare piece-rate profit vs hourly target for tattoo work.

Estimate monthly Twitch sub revenue by tier and partner split.

Compare actual vs dimensional weight for Etsy parcel shipping.

Estimate propane gallons for generator runtime at an event.

Amortize drone battery cost over rated cycle life.

Size on-truck water tank for daily car count and gallons per car.

Model vending machine payback from sales, restock, and fees.

See creator net after platform fee percentage.

Estimate 4K export file size and upload duration from bitrate.

Price multi-night house sitting with pet and extra fees.

Calculate nutrient ml to hit target PPM in a reservoir.

Compute Mel's Mix volume in thirds for raised beds.

Plan seed grams per 1020 tray and total for multiple trays.

Size solar watts and Ah battery bank from daily Wh load.

Compare BTU output by cord for softwood vs hardwood types.

Estimate T-posts and netting rolls for poultry perimeter.

Size inline fan CFM from tent volume and air changes per minute.

Estimate harvested gallons from roof area and rainfall.

Balance browns and greens to target hot compost C:N ratio.

Convert mulch depth and area to cubic yards and cost.

Estimate wedding cake servings using Wilton tier counts.

Estimate bottles needed for a DIY open bar by guest count.

Scale meat and cheese ounces for charcuterie boards.

Compute 5e encounter XP budget by level, party size, and difficulty.

Estimate GM prep hours for a one-shot by length and complexity.

Calculate corn sugar oz to bottle-carbonate homebrew.

Compute telescope field of view and pixel scale for imaging.

Estimate RC gear ratio and top speed from pinion/spur and tire.

Calculate acid dye grams from yarn weight and depth of shade.

Compute roasted weight from green coffee and roast loss %.

Estimate annual electricity savings when upgrading from an older SEER-rated AC to a higher-efficiency unit.

Estimate AC tonnage from conditioned square footage and building factors.

Compute CFM through round duct from diameter and velocity.

Compare annual heating cost between a furnace and a heat pump.

Build a profitable HVAC service call quote.

Size mini-split systems by dividing total load across head capacities.

Estimate gas savings when upgrading furnace efficiency (AFUE).

Estimate additional refrigerant for line set length beyond factory charge.

Estimate installed HVAC price with labor and permit add-ons.

Estimate recommended tank water heater capacity from household size and peak hot-water demand.

Total pipe = straight run + fittings allowance per joint.

Compute drain grade from horizontal run and vertical drop.

Estimate total DWV fixture units for drain sizing.

Build a plumbing job bid with margin on direct costs.

Sum fixture GPM demands for peak simultaneous hot water use.

Size sump pump capacity from catchment area and lift head.

Size septic tank from bedroom count and daily wastewater flow.

Side-by-side material cost for PEX vs copper by linear foot.

Approximate friction pressure loss in water pipe runs.

Ballpark rough-in cost from fixtures and labor hours per fixture.

Suggest wire gauge for a circuit load and check voltage drop against the 3% guideline.

Compute voltage drop and percent loss for a circuit run.

Estimate conduit fill percent and max wire count at 40% fill.

Recommend breaker and wire for EV charger circuit with voltage drop check.

Build electrical job price with margin on direct costs.

Estimate generator kW from essential load and starting surge.

Estimate panel count and payback from usage and production assumptions.

Calculate LED retrofit savings and payback period.

Total load with spare percent → recommended subpanel size.

Estimate monthly kWh and connected amps for commercial lighting.

Estimate linear feet of baseboard from room size and heat loss.

Convert roof area to squares with pitch and waste, then estimate material and labor totals.

Convert squares to shingle bundle count with waste allowance.

Estimate gutter flow capacity and recommended downspout count.

Net siding area with waste and material/labor cost estimate.

Count posts, rails, and pickets for a fence run.

Compute pitch, angle degrees, and slope multiplier from rise and run.

Rule-of-thumb max joist span from lumber size and spacing.

Total shingle weight on structure from squares and lbs/square.

Gallons needed for exterior paint from surface area and coverage rate.

Calculate bid price, net profit, and margin from materials, labor hours, overhead, and markup.

Compare original vs revised bid margin after scope/cost changes.

Volume in cu yd and 80 lb bags from slab dimensions.

Low/high remodel estimate from room size and $/sq ft range.

Side-by-side sub bid compare with low bid and spread.

Sheets and mud from wall/ceiling surface area with waste.

Interior paint gallons for walls and ceiling.

Effective hourly and job cost for day-rate vs piece-rate crews.

Overhead recovery add-on per job from monthly overhead and job duration.

Break-even days/years between renting and buying equipment.

Contingency $ and % from job value and risk tier.

Mulch volume in cubic yards and bag count from area and depth.

Sod order sq ft including waste and cost.

Gravel volume converted to tons with delivery cost estimate.

Total zone GPM demand for irrigation design check.

Blocks needed for retaining wall face area.

Pavers and base gravel volume for patio install.

Brick count and mortar bags for a brick wall.

Count concrete masonry units for a wall.

Rebar pieces and weight for a slab or footing run.

Bags of concrete for cylindrical post holes.

Map CIDR prefix length to subnet mask, total addresses, and usable host count for IPv4 networks.

Find the CIDR prefix that fits a required number of IP addresses.

Convert IPv4 octets into IPv4-mapped IPv6 address notation for dual-stack routing.

Model how RTT and packet loss reduce effective data transfer speed on a connection.

Estimate DNS change visibility window from TTL values and resolver refresh cycles.

Map OUI prefix octets to common network hardware vendors for inventory and troubleshooting.

Estimate usable capacity and fault tolerance across common RAID levels.

Convert file size and link speed into estimated transfer time.

Convert storage values between decimal SI and binary IEC units.

Calculate end-to-end optical power budget for fiber links.

Rough-estimate regex execution cost from pattern complexity and input length.

Translate Unix epoch seconds into days, hours, and minutes from the Unix epoch.

Calculate JSON payload weight and minification compression ratio.

Estimate Base64 encoded length and overhead from raw byte size.

Estimate how many times a cron job runs per day, week, or month.

Convert 24-bit hex color values to RGB channels and optional alpha.

Estimate password hash computation time from bcrypt cost factor.

Convert between binary bit counts and byte/hex/text representations.

Calculate change percentage and similarity score between two text versions.

Map ASCII character codes to decimal, binary, and hex formats.

Ballpark monthly AWS spend from compute, storage, and egress.

Ballpark monthly Azure costs for VMs, disks, and outbound data.

Ballpark monthly GCP spend for compute and object storage.

Estimate LLM API spend from token volume and per-1K pricing.

Estimate memory for storing AI embeddings in a vector database.

Estimate serverless compute cost from invocations, duration, and memory.

Compute MRR, ARR, and LTV from subscriber count, ARPU, and monthly churn.

Ballpark app build cost from features, complexity, and developer rates.

Plan API rate limits from requests per window and user concurrency.

Translate SLA percentages like 99.9% into allowed outage minutes.

Decode 4-band resistor color codes into resistance in ohms.

Solve for voltage, current, resistance, and power in DC circuits.

Find the series resistor value for a given supply voltage and LED forward voltage.

Compute output voltage in a resistive voltage divider circuit.

Estimate PCB trace width needed to carry a given current safely.

Calculate how many hours a battery will run at a given load current.

Compute RC time constant and capacitor charge times.

Recommend copper wire gauge for a target current load.

Convert dB to power and voltage ratios relative to a reference.

Size a desktop PSU from CPU, GPU, and system component power draw.

Model how page load time affects bounce rate and conversion.

Project SEO revenue from keyword volume and conversion funnel metrics.

Compute impressions, clicks, and cost from CPM/CPC ad metrics.

Compute CRO conversion rate and projected conversions at scale.

Estimate effective email reach accounting for bounces and opens.

Compute social media engagement rate vs follower count.

Estimate whether an A/B test result is statistically significant.

Encode-side planner: given a delivery bitrate and runtime, how large is the file you will upload or host? Includes audio so a 128 kbps track does not surprise you.

Compute screen dimensions from aspect ratio and width or height.

Compute ROI percentage from investment cost and return gained.

A 5K is 5,000 meters, not 5 kilometers on the nose if your watch is sloppy. Divide meters by 1,000. Track races, building plans, and “how far was that hike” all live in this split.

US height, ceiling height, and lumber still arrive in feet. Meter plans do not. One foot is exactly 0.3048 m — not “about a third.” Use this when a listing says 10 ft ceilings and the architect works in meters.

Monitor diagonals, waist measurements, and photo prints still come in inches. Clothing charts in Europe come in cm. Multiply inches by 2.54. That factor is exact, not a kitchen guess.

US road trips and marathon shirts speak miles. Highway signs in most of the world speak km. One mile is 1.609344 km. “Times 1.6” is fine in the car; use the exact factor for a race or a fuel log.

American football and golf still sell yards. World Athletics and FIFA sell meters. A yard is 0.9144 m, so a 100-yard field is not a 100 m track. Do not mix them on a training log.

Wrench sizes, phone specs, and rain totals often arrive in mm. Hardware aisles in the US still think in fractions of an inch. Divide mm by 25.4. A “25 mm” socket is not 1 inch; it is 0.984 in.

Height charts, inseam tables, and sewing patterns swap cm and inches constantly. Divide cm by 2.54. A 180 cm person is about 5 ft 11 in — the leftover 0.16 in is why both sides of a doorway argue about the last fraction.

Building codes in meters, US listings in feet. Multiply meters by 3.28084. A 3 m ceiling is 9.84 ft, not “10 feet” unless you are rounding for a Facebook comment.

A 10K is 6.21 miles. Divide km by 1.609344. US cars still show mpg; European trip computers show L/100 km and km/h. This page is only the distance half — speed has its own converter.

Charts, flight plans, and AIS tracks use nautical miles because one nmi is one minute of latitude. That is 1.852 km exactly — longer than a statute mile. Do not drop a flight plan into the land-mile converter.

Bacteria, coatings, and chip features sit in micrometers. Light wavelengths and process nodes sit in nanometers. Multiply µm by 1,000. A “5 µm” particle is 5,000 nm — not 5 nm.

A light year is a distance, not a birthday. It is how far light travels in one Julian year: about 9.461 trillion km. Proxima Centauri is 4.25 ly, not “four years away in a 747.”

Horse racing still prints furlongs. Eight furlongs make a mile. A “6f” sprint is 0.75 mi. If you only remember the Derby distance, this is the rest of the card.

A cubit was elbow to fingertip. History books do not agree on one length. This page uses the common short cubit of 18 inches (45.72 cm) so Noah’s Ark worksheets and museum labels have a single, labeled stick. It is not a royal cubit.

A league was roughly an hour’s walk, which is why Jules Verne’s 20,000 leagues is a cartoon of distance. This page uses the land league of 3 miles (4.828 km). Sea leagues differ. Read the footnote on your map.

Body weight, luggage, and gym plates: kg on the passport, pounds on the US scale. Multiply kg by 2.20462. A 23 kg bag is 50.7 lb — over many airline “50 lb” stickers if you packed to the kg limit.

Coffee bags, protein scoops, and postage: grams on the label, ounces in US recipes. Divide grams by 28.3495. This is the avoirdupois ounce (16 in a pound), not the troy ounce jewelers use.

Sixteen avoirdupois ounces in a pound. Shipping labels and baby weight still mix them: 7 lb 8 oz is 120 oz total. Multiply pounds by 16. No troy, no fluid ounces.

Pills, caffeine, and lab reagents print milligrams. Recipes print grams. Divide mg by 1,000. A 500 mg tablet is 0.5 g — not 500 g. That mix-up is how people scare themselves with supplement labels.

UK body weight still comes in stone. One stone is 14 pounds. “11 st 4 lb” is 158 lb, not 11.4 of anything. Americans searching this are usually reading a British forum.

A metric ton (tonne) is 1,000 kg. Shipping, carbon, and grain use it. It is not a US short ton (2,000 lb) or a UK long ton (2,240 lb). If the bill of lading says “ton” without “metric,” ask.

US recipes still say 8 oz of chocolate. European scales only know grams. Multiply ounces by 28.35. If the recipe meant a fluid cup, you are in the wrong aisle — that is volume.

US body weight and barbell math into the kg plates the rest of the gym already uses. Divide pounds by 2.20462. 150 lb is 68.0 kg, not “70 kg unless you are rounding for a form.”

A metric carat is 0.2 g, defined in 1907 so jewelers would stop arguing. A 1 ct diamond is 0.2 g — the size you see is cut, not this mass. Gold “karat” (purity) is a different word on purpose.

Daltons (u) are how chemists weigh atoms. Carbon-12 is defined as 12 u. The gram is 6.022 × 10²³ of those, which is why a mole of carbon is 12 g. This page is for lab sheets, not grocery bags.

A British long ton is 2,240 lb (20 hundredweight). Ships and old coal invoices use it. A US short ton is 2,000 lb. If a UK document says “ton” it might be this one — 240 lb of difference per ton.

US gravel, scrap, and HVAC freight: a short ton is 2,000 lb. Dump-truck quotes in “tons” almost always mean this. Multiply by 2,000. Do not pay a long-ton price for a short-ton pile.

Ammunition, arrows, and old pharmacy weights still use grains. One grain is 64.79891 mg. A “115 gr” 9 mm bullet is 7.45 g. This is not a grain of rice.

US customary dynamics: a slug is the mass that accelerates at 1 ft/s² when you push with 1 lbf. It is about 14.59 kg. If your textbook mixes slugs and pounds-mass, this page is the adult in the room.

Pawn shops and gold buyers still quote pennyweights (dwt). 20 dwt make a troy ounce. One dwt is 1.555 g. If someone prices scrap in dwt and you think in grams, convert before you nod.

Weather apps, ovens, and fever debates. Multiply °C by 9/5 and add 32. Room temperature 20 °C is 68 °F. Body temperature 37 °C is 98.6 °F. The “times two plus 30” trick is only for sidewalks.

US thermostats still speak Fahrenheit. Science and most of the planet speak Celsius. Subtract 32, then multiply by 5/9. 72 °F indoors is 22.2 °C, not “22 unless you like arguing about hoodies.”

Labs and gas laws want kelvin because zero means zero motion, not “really cold in Celsius.” Add 273.15. You never write a degree sign on K. 25 °C room temp is 298.15 K.

Datasheets list 298 K and you wanted “was that a warm lab?” Subtract 273.15. 298.15 K is 25 °C. Liquid nitrogen’s 77 K is −196 °C.

When a US weather number has to enter an ideal-gas problem: convert °F to °C in your head, then add 273.15 — or let this page do both. 68 °F is 293.15 K.

A paper lists 255 K overnight on Mars and someone asks “what’s that in weather units?” Subtract 273.15, then × 9/5 + 32. 255 K is about 0 °F. 300 K is 80.3 °F.

Rankine is absolute Fahrenheit: 0 °R is absolute zero, and the degrees are the same size as °F. Subtract 459.67. Thermodynamics homework in US customary units lives here. 530 °R is about 70 °F.

Old European cheese caves and Alpine recipes still print °Ré. Water freezes at 0 °Ré and boils at 80 °Ré. Multiply by 5/4 to get Celsius. 80 °Ré is 100 °C, not a medium-rare steak.

UK recipes say Gas Mark 4 and a US oven only has a knob in °F. Mark 1 is 275 °F, then about +25 °F per mark. Mark 4 is 350 °F — the everyday cake setting. This is British gas-oven tradition, not a lab scale.

When a US customaries thermodynamics problem wants an absolute temperature but you measured Celsius: convert to kelvin, then × 9/5. 20 °C is 527.67 °R. Absolute zero is 0 °R on both sides of the ocean.

Apartment listings in Europe print m². US flooring quotes print square feet. Multiply by 10.7639. A 50 m² studio is 538 ft² — not “500 unless the agent rounded in your favor.”

US land: one acre is 43,560 ft², a chain-and-furlong leftover that refused to die. A quarter-acre lot is 10,890 ft². Multiply acres by 43,560. Soccer-field metaphors are not a survey.

Farms and conservation land: a hectare is 10,000 m², about 2.471 acres. EU grants speak hectares. US county GIS speaks acres. Multiply ha by 2.47105.

City limits and national parks: divide km² by 2.58999. Los Angeles is about 1,300 km², not a “mile” number until you convert. One km² is 0.386 mi².

Phone screens, stamps, and wound measurements. Multiply in² by 6.4516. A 1×1 inch square is 6.45 cm². Do not convert the diagonal and then square the wrong number.

Carpet and turf still sell by the square yard in the US. Metric rolls sell by the m². Multiply yd² by 0.836127. Ten square yards is 8.36 m², not 10.

Car tanks, paint, and aquariums. This is the US liquid gallon (3.785 L), not the UK gallon (4.546 L). Divide liters by 3.785. A 50 L tank is 13.2 US gal. Using the UK gallon will short you fuel.

Bottles, baby formula, and espresso. Divide mL by 29.5735 for US fl oz. A 500 mL water bottle is 16.9 fl oz, which is why the label says both. UK fl oz is different; this is US.

Fill-up math when the pump is in gallons and the car computer is in liters. Multiply US gallons by 3.785. A 15 gal fill is 56.8 L. UK gallons would overstate that by about 20%.

US customary cup is 240 mL in nutrition labels and 236.6 mL in the true fluid-cup (8 fl oz). This page uses the 8 fl oz cup (236.6 mL). A “metric cup” in Australia is 250 mL. If the cake falls, check which cup the author owned.

US tablespoon is 14.79 mL (½ fl oz). UK/AU tablespoons are often 15 mL. Medicine “tablespoons” on old bottles were a mess — use the mL syringe. One US tbsp of oil is not a UK tbsp.

US teaspoon is 4.93 mL. Metric baking teaspoons are 5 mL. For medicine, 5 mL is the teaspoon they meant. Do not use a kitchen tea spoon from the drawer; those wander.

Shipping containers, HVAC airflow, and mulch. Multiply m³ by 35.315. One cubic meter is 35.3 ft³. A 40 m³ truck is 1,413 ft³ — not a 40-foot container’s nickname.

Engine displacement: a “350” small-block is 350 in³, about 5.7 L (5,735 cc). Multiply in³ by 16.387. One liter is 1,000 cm³. This is why 5.0 L and 302 in³ show up on the same valve cover.

US liquid pint is 473 mL (16 fl oz). UK pint is 568 mL. A “pint of ice cream” in the US is often 14–16 fl oz of marketing. This page is the US liquid pint: 0.473 L.

Motor oil and soup stock: a US quart is 0.946 L, almost a liter but not. Four quarts make a US gallon. If the cap says 5W-30 1 qt, you are 54 mL short of a liter bottle.

US fl oz × 29.57 = mL. An 8 oz cup of coffee is 237 mL. UK fl oz is 28.4 mL. Bottle labels that say 12 fl oz are 355 mL — the beer can you already know.

A US bushel is 35.239 L of volume. Grain “bushels” on a scale ticket are often a weight standard (56 lb of corn, etc.), not a filled basket. This page is the struck volume bushel. Ask which one the elevator meant.

US farm ads in acres, EU paperwork in hectares. Divide acres by 2.471. Ten acres is 4.05 ha. A 160-acre quarter-section is 64.7 ha.

One square mile is 640 acres — a US survey section. Ranch listings and wildfire maps still use both. Multiply mi² by 640. A 36 mi² township grid is 23,040 acres.

Drive makers sell decimal GB (1,000 MB = 1 GB). Windows often shows GiB (1,024³). A “500 GB” disk showing 465 GB is not broken — it is two dictionaries. This page uses SI decimal: divide MB by 1,000.

NAS shelves and video libraries. Divide GB by 1,000 for decimal TB. 4,000 GB is 4 TB on the box. macOS 10.12+ also uses decimal; older Windows “TB” was often tebibytes. Know which UI you are reading.

Email attachments and tiny logs. SI: 1,000 KB = 1 MB. People still type 1,024 because of kibibytes. This page divides by 1,000. A 5,000 KB photo is 5 MB decimal, 4.77 MiB in Finder-old-speak.

Eight bits make a byte. Networks advertise bits (Mbps). Disks advertise bytes. Divide bits by 8. A 1,000,000 bit dump is 125,000 bytes — not a megabyte of disk unless you meant megabits.

Divide bytes by 1,000 for SI KB. Old textbooks divided by 1,024 (KiB). A 2,048-byte packet is 2.048 KB decimal or 2 KiB. Pick the dictionary your protocol spec uses.

Datacenter talk. 1,000 TB = 1 PB in SI. A 10,000 TB estate is 10 PB. Tape libraries and object stores quote this. Your laptop does not.

The ISP sold you 100 Mbps. The download window shows MB/s. Divide by 8. 100 Mbps is 12.5 MB/s in a perfect vacuum. Real TCP, Wi-Fi, and VPN eat a slice. If you see 11 MB/s on a “100 megabit” line, you are fine.

10 GbE and fiber quotes. Divide Gbps by 8. 10 Gbps is 1.25 GB/s — faster than many disks. A “gigabit” home plan is 1 Gbps = 0.125 GB/s, not a gigabyte a second. Sales teams enjoy that confusion.

KiB is 1,024 bytes. KB here is 1,000 bytes. Multiply KiB by 1.024. RAM and old Windows file sizes think in kibibytes even when the UI says KB. This page is the handshake between those two lies.

1 MiB = 1,048,576 bytes. 1 MB = 1,000,000 bytes. Multiply MiB by 1.048576. A 700 MiB ISO is 734 MB on a decimal progress bar. That is why two windows never match.

1 GiB = 2³⁰ bytes. 1 GB = 10⁹ bytes. Multiply GiB by 1.073741824. A 931 GiB “1 TB” disk is the classic unboxing surprise: 1,000,000,000,000 bytes ≈ 931 GiB.

1 TiB = 2⁴⁰ bytes. 1 TB = 10¹² bytes. Multiply TiB by 1.0995. An 8 TiB volume in TrueNAS is 8.80 TB decimal. RAID-Z does not change the unit; it changes how many of them you keep.

How long to move a file if the pipe is what they claimed. Time in seconds = size in GB × 8,000 ÷ Mbps. A 4.7 GB DVD over 50 Mbps is about 12.5 minutes before Wi-Fi and TCP take a cut. This is a ceiling on hope, not a promise.

Megapixels = width × height ÷ 1,000,000. 1920×1080 is 2.07 MP, not “1080p magic.” 4K UHD 3840×2160 is 8.3 MP. Phone “48 MP” modes are sensor marketing plus pixel binning — convert the actual still you exported.

Uncompressed-ish math: size in bytes = bitrate (bits/s) × seconds ÷ 8. A 320 kbps MP3, 4 minutes, is about 9.6 MB. CD audio 1,411 kbps is 10.6 MB per minute. Variable bitrate files will miss this — it is an average-rate sketch.

Multiply hours by 60. A 1.5 hour meeting is 90 minutes. Decimal hours on a timesheet (7.25 h) are 435 minutes, not 7 hours 25 minutes — that mix-up is how payroll tickets start.

Multiply days by 24. A “two-day” shipping promise is 48 hours if they meant calendar days, and something shadier if they meant business days. This page does not skip Sundays.

Multiply weeks by 7. Pregnancy “weeks” and sprint “weeks” both use this, then life adds exceptions. Two weeks is 14 days. A six-week notice is 42 days, not “a month and a bit” unless you like ambiguity.

This uses the Julian year of 365.25 days (31,557,600 s) so leap years are averaged. One year is 365.25 days, not 365. Contracts that say “365 days” are being literal; astronomy is not.

Multiply seconds by 1,000. A 60 Hz frame is 16.7 ms. API timeouts in seconds vs ms are a classic outage: 5 s is 5,000 ms, not 5. If a config file is silent, assume you are about to be wrong.

Multiply mph by 1.609344. 60 mph is 96.6 km/h, not 100. Rental cars and speed-limit photos fail this constantly. The inverse page is km/h to mph if your dash swapped overnight.

Multiply m/s by 3.6. Physics problems live in m/s; dashboards live in km/h. 10 m/s is 36 km/h. A 100 m sprint in 10 s is an average 10 m/s — not a highway speed, just a very committed 36 km/h.

A knot is one nautical mile per hour. Multiply by 1.15078 for statute mph. 10 kn is 11.5 mph. Weather “20 knot winds” are not 20 mph — they are stronger on a US car speedometer.

Multiply ft/s by 0.3048. Ballistics and old US textbooks love ft/s. 88 ft/s is 60 mph, which is 26.82 m/s. A 3,000 ft/s muzzle velocity is 914 m/s.

Mach 1 is the speed of sound. This page uses 340.29 m/s (about 761 mph) — dry air, 15 °C, sea level. Up high, the air is colder and Mach 1 is slower in mph. Treat airline “Mach 0.85” as a cruise ratio, not a ground-speed tattoo.

A century is 100 years. Multiply. History essays already know this; the page exists because search boxes do not. Two centuries is 200 years. We use the same Julian year as the years-to-days tool if you chain them.

Divide µs by 1,000,000. Database latency of 800 µs is 0.0008 s. A million microseconds is one second. If your profiler says µs and your SLO says ms, you are one zero away from a bad meeting.

Divide ns by 1,000,000 to get milliseconds. A CPU cycle is a few ns. 1,000,000 ns is 1 ms. Network “30 ms” is 30 million nanoseconds. Profilers that print ns make people think the function is slow when it is not.

Frame time in ms = 1,000 ÷ Hz. 60 Hz is 16.67 ms. 144 Hz is 6.94 ms. If the GPU misses that window, you skip a frame. High refresh is smaller windows, not free frames.

Pace is time divided by distance. Type kilometers and minutes (decimals allowed: 28.5). You get min/km and min/mile. A 5 km in 28:00 is 5:36 /km or about 9:01 /mi. Watches already do this; this page is for the spreadsheet on the kitchen table.

A small calorie (cal) is 4.184 J — heat to warm 1 g of water 1 °C. Food “Calories” on a US label are kilocalories (kcal): 1 kcal = 4,184 J. If you paste 2,000 from a snack wrapper without noticing the capital C, you are off by a thousand.

Your electric bill is in kWh. Physics problems want joules. 1 kWh = 3.6 MJ exactly (1,000 W × 3,600 s). A 30 kWh EV pack is 108 MJ. That is energy stored, not how far you will get in the rain.

Mechanical horsepower is 745.7 W. A 150 hp engine is 112 kW. Metric PS is 735.5 W — close, not the same. Peak dyno hp is not what the wheels see. Convert the number on the spec sheet, then stay humble.

US furnaces and AC still speak BTU. Electricity speaks kWh. Divide BTU by 3,412. 12,000 BTU/h is a “1 ton” of cooling and 3.52 kW if it ran an hour — note the /h: that is power. This field is energy (BTU, not BTU/h).

Divide pascals by 6,894.76. Atmospheric pressure 101,325 Pa is 14.70 psi. Tire stickers in kPa: 220 kPa is 220,000 Pa ≈ 31.9 psi. Do not put 220 in this box and call it 220 Pa.

One bar is 100,000 Pa, about 14.50 psi — almost one atmosphere (14.70). European tire pumps in bar: 2.2 bar is 31.9 psi. SCUBA and espresso machines live here too. Close to atm, not the same.

Standard atmosphere is 101,325 Pa by definition. Chemistry problems still say “2 atm.” Multiply. 2 atm is 202,650 Pa or 2.026 bar. Weather “1013 mbar” is about 1 atm, not exactly unless you like rounding.

An electronvolt is tiny: 1.602176634 × 10⁻¹⁹ J, defined from the elementary charge. Hydrogen’s 13.6 eV ionization is 2.18 × 10⁻¹⁸ J. Particle physics uses MeV and GeV; multiply by a million or a billion first.

Divide kW by 0.7457 (or multiply by 1.341). A 100 kW electric motor is 134 hp. EV brochures already did this; ICE dyno sheets sometimes did not. Metric PS is 1.36 hp per kW — close enough to start a fight.

A Celsius heat unit is the heat to raise 1 pound of water by 1 °C — about 1,899 J. Old HVAC and process papers use CHU. If you expected BTU, you are on the Fahrenheit twin (1 lb × 1 °F). Do not mix them in a load calc.

A US cup of spooned all-purpose flour is about 120 g. Scoop-and-level from the bag can hit 140 g and dry out a cake. Weigh if the crumb matters. Bread flour is denser; cake flour is lighter.

White granulated sugar sits near 200 g per US cup. It packs less drama than flour. Caster/superfine is similar; powdered sugar with cornstarch is closer to 120 g and is a different page in spirit.

A US stick is ½ cup, 8 tablespoons, 4 oz, 113 g. European blocks are often 250 g. If a UK recipe says “8 oz butter,” that is two US sticks, not a European brick.

Packed light or dark brown sugar is about 220 g per US cup. “Packed” means you pressed it. A loose scoop can miss 30 g and flatten cookies. Light and dark weigh nearly the same; molasses is the flavor, not the scale.

Unsweetened cocoa powder is fluffy. A US cup is about 85 g sifted/spooned. Dutch-process vs natural does not change the gram target as much as how hard you tap the cup.

A US tablespoon of honey or maple syrup is about 21 g. Oil is closer to 14 g. A “heaping” spoon is not a tablespoon. Warm honey levels itself; cold honey lies.

Old-fashioned rolled oats are about 90 g per US cup. Quick oats similar. Steel-cut are denser (~160 g). Overnight-oat blogs that say “1 cup” usually mean rolled.

White long-grain usually triples: 1 dry cup → about 3 cooked. Brown rice is closer to 2–2½. Risotto soaks differently. This is a pot estimate, not a lab yield.

Milk and water weigh almost the same in a measuring cup. A US cup is 236.6 mL (8 fl oz). Nutrition labels round to 240 mL. Whole milk is slightly denser; it will not save a sauce that was 20 mL short.

A US ¼-oz packet of active dry or instant yeast is 7 g, about 2¼ teaspoons. Fresh cake yeast is a different animal (roughly 3× by weight). Instant and active dry substitute 1:1 in most home doughs if you treat the rise time kindly.

A kitchen pinch is roughly 1/16 teaspoon — two fingers, not a three-finger grab. Chefs argue. If the soup is for guests, weigh 0.3 g of table salt and stop pretending.

8 US fl oz make a cup. A 12 oz can is 1½ cups. UK fluid ounces are 28.4 mL, not 29.6 — close until you scale a catering recipe.

Four US quarts make a gallon. Stock pots and paint cans still speak this language. An imperial gallon is 4.55 L, not 3.79 L — do not mix them in a brine.

A pinch of table salt is about 0.36 g. Kosher flakes need more volume for the same sodium. If a dough formula lists salt as 2% of flour, use the scale, not your fingers.

UK Gas Mark 4 is 180 °C (350 °F), the everyday sponge setting. Mark 6 is 200 °C. Fan ovens usually want 15–20 °C less than a still oven. The thermostat in the door is not a lab probe.

An American 350 °F cake is UK Gas Mark 4. The mark scale jumps about 25 °F per number. Round to the nearest mark your knobs actually have. Pizza steel at 500 °F is past Mark 9 — just use the number.

Same batter volume means same base area: πr² = side². An 8-inch round matches a 7.1-inch square, which nobody sells, so you buy 8-inch square and expect a slightly shorter cake. Depth still matters.

Hydration is water ÷ flour × 100. Starter is extra flour and water if you include it. 70% on bread flour handles easily; 80% wants a wet-hand technique. Whole grain drinks more than the percentage admits.

Want a 1½× batch? Multiply every gram the same. Yeast and salt scale linearly in home kitchens. Baking powder in a cake that already fills the tin does not — the pan volume is the real limit.

Refractometers speak Brix; hydrometers speak SG. Unfermented wort: SG ≈ 1 + Bx / (258.6 − (Bx/258.2)×227.1). After fermentation alcohol fools a refractometer — use a correction, not this page alone.

Mass = moles × molar mass. Water is 18.015 g/mol, NaCl 58.44. The bottle’s formula weight is the one that counts, not a memory from first-year chemistry.

λ = c / f in vacuum. FM 100 MHz is 3 m. Wi-Fi 2.45 GHz is 12 cm. In cable the velocity factor shortens it. Do not size an antenna from this and skip the dielectric.

I = 10⁻¹² × 10^(L/10) W/m². 0 dB SPL is the quiet threshold, 60 dB a chat, 120 dB a pain rumor. Loudness is not intensity; +10 dB is 10× intensity and roughly twice as loud to a human ear.

Lux = lumens ÷ square meters, if every lumen landed evenly on that patch. An 800 lm bulb over 10 m² is 80 lx on paper. Walls, shades, and inverse-square eating the corners are not in the slider.

One foot-candle is one lumen per square foot, 10.764 lux. US building specs still print fc; EU prints lux. A 50 fc classroom is about 538 lx.

π rad is 180°. A full turn is 2π rad or 360°. Calculators in radian mode will ruin a trig exam if you type 90 thinking it is a right angle.

A right angle is 100 gon (gradians), 90°, π/2 rad. Surveying in some countries still uses gon. A full circle is 400 gon. Do not mix gon and degrees in a bearing without saying so.

ω = rpm × 2π / 60. A 1,800 rpm motor is 188.5 rad/s. Synchronous 60 Hz four-pole machines sit near 1,800 rpm before slip. The shaft does not care about degrees unless you convert again.

V = I × R. Enter any two, solve the third. Power is V × I. This is DC or RMS-with-a-straight-face. Reactance, power factor, and a warm resistor are not fields.

1 F = 1,000,000 µF. A 100 µF electrolytic is 0.0001 F. Supercapacitors that brag in farads are the exception. nF and pF are further decimal slides.

1 H = 1,000 mH. A 10 mH choke is 0.01 H. Speaker crossovers live in mH; power magnetics sometimes in H. The core material is not in the factor.

1 weber = 10⁸ maxwell. Tesla is flux density (Wb/m²); maxwell is the CGS flux. Old magnet catalogs still print Mx. New papers should not.

1 Ci = 3.7×10¹⁰ Bq, historically 1 g of ²²⁶Ra. A smoke-alarm source is kBq, not Ci. This is activity, not dose. Handling rules live in a license, not a slider.

1 Sv = 100 rem. A millisievert is 0.1 rem. Occupational limits are a regulation, not this factor. Quality factors for neutrons are already supposed to be inside the sievert you typed.

1 stoke = 100 centistokes = 10⁻⁴ m²/s. Engine oil grades (5W-30) quote cSt at 40 °C and 100 °C. Water is about 1 cSt at 20 °C. Dynamic viscosity needs density too.

1 poise = 0.1 Pa·s. Water is about 0.01 P (1 cP) at 20 °C. Honey is tens of poise. Centipoise is the lab slang: 1 cP = 0.001 Pa·s.

Q = ṁ / ρ. Water near 1,000 kg/m³: 1 kg/s is 1 L/s. Air at 1.2 kg/m³ needs a much larger duct for the same kilograms. Compressible flow at high Mach is not this equation.

E = hc / λ. A 550 nm green photon is about 2.25 eV. X-rays are picometers and keV. The page uses the SI values of h and c, vacuum, one photon — not a laser pulse energy.

[H⁺] = 10^(−pH) mol/L as a dilute-water approximation. pH 7 is 1×10⁻⁷ M. Strong acids, high ionic strength, and 37 °C blood chemistry all argue with that textbook line. Use activity if you are publishing.

P(W) = 10^((dBm − 30)/10). 0 dBm is 1 mW. 30 dBm is 1 W. Wi-Fi EIRP limits are a regulator’s problem; this is just the log.

rem = px ÷ root. At the usual 16 px root, 24 px is 1.5 rem. Users who enlarge the root are why you used rem in the first place. Hard-coding 16 px in media queries fights them.

em is relative to the parent’s font-size, not the html root. Nested 1.2 em compounds. Padding in em grows with the text; that is either elegant or a layout bug.

CSS says 1 pt = 1/72 in and 1 in = 96 px, so 12 pt is 16 px. Print at 300 DPI is a different grid. Word’s “12 pt” on paper is not your laptop’s CSS pixel.

Pixels = inches × DPI. A 4×6 print at 300 DPI is 1200×1800 px. Screens often assume 96 DPI in CSS. If the print shop said 300, do not export at 72 and hope.

px = (cm / 2.54) × DPI. A 10 cm bar at 300 DPI is 1,181 px. A4 width 21 cm at 300 DPI is 2,480 px. Packaging die-lines still want millimeters and bleed; this is the raster step.

Height = width × (ratio height / ratio width). 1920×1080 is 16:9. Instagram’s 1:1 is a crop, not a camera sensor. Letterboxing is you refusing to crop.

box-shadow: x y blur spread rgba(...). Soft UI is usually 0 8px 24px at 12–20% black. Inset is a checkbox, not a different physics. Multiple shadows mean more declarations, not a larger spread.

Paste #1a73e8 or 1a73e8. Shorthand #1ae expands. RGBA is the same three bytes plus an alpha you type. Design tokens that mix hex and rgb() are how themes drift.

Naive uncalibrated RGB→CMYK: K = 1 − max(R,G,B); C = (1−R−K)/(1−K). Press CMYK needs an ICC profile. This is a first look, not a contract proof. Pure screen red will not print as a fire engine.

HSL is how humans tweak a brand blue: keep H, drop L for a hover. Hex is what CSS still loves. Saturation and lightness are 0–100%. Hue wraps at 360.

Reduce part:whole by their gcd. 16 of 100 is 4:25. 1:1 is 50 of 100. Mix ratios for resin are usually mass, not this volume percentage — read the jug.

Column = (container − gap × (columns − 1)) / columns. A 12-column 1200 px grid with 16 px gutters is 84 px columns. Bootstrap’s 30 px gutter era is why old comps look airy.

Modular scale: size × ratio^n. Major third (1.250) is polite for UI. Perfect fifth (1.500) jumps like a poster. Pick a ratio and stop inventing 17 px body text because Figma snapped.

px = vw% × viewport width. 50 vw on a 1280 px layout is 640 px. 100 vw includes scrollbar quirks on some desktops. Mobile address bars resize the visual viewport — fluid type can jump.

Unitless line-height 1.5 on 16 px type is 24 px. Headlines often 1.15–1.3; body 1.45–1.7. A length in px will not inherit as nicely as a unitless multiplier.

Seconds = file MB × 8 / Mbps. A 25 MB installer on 50 Mbps is 4 seconds in a vacuum. The other GB-scale page is for discs; this one is the “how long will this PDF take on hotel Wi-Fi” version.

Ratio = compressed ÷ original. 1.6 / 8 = 0.2, an 80% cut. WebP vs JPEG is a codec argument; this is just the two file sizes. Do not chase 0.05 on a screenshot full of type.

Paste a data URL or raw base64. The browser draws it here; nothing is uploaded. Size is about length × 3/4 bytes. Huge strings can freeze a tab — that is your RAM, not a server.

Lowercase, strip accents, spaces to hyphens, drop punctuation. encodeURIComponent is a different hammer for query strings. A slug is for /how-to-convert-meters-to-feet, not for hiding an API token.

Seconds since 1970-01-01 UTC. 1,700,000,000 is 2023-11-14. If the number has 13 digits, someone gave you milliseconds — divide by 1,000. Local DST is a display issue; the epoch is UTC.

US, UK, EU, and Mondopoint (cm) through Paris points: EU × 2/3 ≈ foot length in cm. Brands last differently. A US men’s 9 is about EU 42; women’s US 9 is about EU 40. Try the pair on.

US sizes map to inner diameter (about 11.63 + 0.81 × size mm) and circumference. UK uses letters. EU often prints circumference in mm. Knuckles and temperature move the fit more than 0.25 US.

Women’s dress ballpark: US 8 ≈ UK 12 ≈ EU 40 ≈ AU 12. Letters: S ≈ US 6, M ≈ 10, L ≈ 14. Vanity sizing ate the 1990s. Measure bust/waist/hip and use the brand’s chart.

Band in inches (US/UK) and cup letter. EU bands are centimeters rounded to 5 (34 → 75). Cup letters drift after D: UK DD vs US DD/E is a forum war. Sister sizes (34C / 32D) share cup volume, not this converter’s job.

US fitted size is roughly head circumference ÷ π in inches (7¼ ≈ 22.8 in / 58 cm). Stretchy beanies ignore this. Measure above the ears, not over a ponytail.

L/100km = 235.215 / US mpg. Higher mpg is better; higher L/100km is worse. UK mpg uses the imperial gallon, so the constant is 282.5 — use the sibling page’s note if the brochure is British.

US mpg = 235.215 / (L/100km). UK mpg = 282.481 / (L/100km). A European 6.0 L/100km sticker is about 39 US mpg. Window stickers mix these on purpose if you import a car.

Default 0.404 kg/mile is a US EPA passenger-car average. Your truck is higher; a full EV is the grid’s carbon, not zero. This is tailpipe-style accounting for a planning conversation, not an offset invoice.

kWh = watts × hours / 1,000. A 60 W bulb for 5 hours is 0.3 kWh. Nameplate watts on a fridge are not the same as the compressor’s duty cycle.

Cost = watts × hours / 1000 × $/kWh. A 1,500 W space heater for 4 hours at $0.16/kWh is $0.96. The supply rate on the bill is the one that matters, not a national average.

kWh/day ≈ (array W / 1000) × peak sun hours. A 400 W panel in 4.5 PSH is 1.8 kWh before dirt, heat, and inverter loss (often 0.75–0.85). NREL sun-hour maps beat a guess.

1 US gpm = 3.785 L/min. A 2.5 gpm showerhead is 9.5 L/min. UK gallons are larger. Fixture laws care about the number on the aerator, not the pipe diameter.

Force 5 is a fresh breeze, about 19 knots / 22 mph. Force 8 is a gale. Force 12 is hurricane language. The original scale was sea state, not an anemometer. We use common midpoint knots.

225/55R17: sidewall = 225 × 0.55 mm; overall diameter = rim + 2 × sidewall. Changing plus-size wheels without matching diameter fools speedometers. Load index is not in this geometry.

mph ≈ RPM / ratio × tire circumference × 60 / 63,360. Overall ratio is gear × final drive × (transfer case). Torque converter slip in autos is extra. Use the tire-size page for diameter.

BMI = kg / m² = 703 × lb / in². Same index, two unit systems. It does not know muscle, bone, or why a powerlifter and a couch get the same number. Categories are public-health bins, not a diagnosis.

Divide mg/dL by 18. A US 100 mg/dL fasting reading is 5.6 mmol/L. Meters and lab slips switch countries without warning. This is unit math, not a treatment plan.

Total cholesterol: mmol/L = mg/dL ÷ 38.67. A US 200 mg/dL is 5.2 mmol/L. Triglycerides use ÷ 88.57 — wrong factor, wrong lecture. LDL/HDL use the cholesterol factor.

Naegele: EDD = first day of last period + 280 days (40 weeks). Cycles that are not 28 days shift this. Dating scans override the calendar. This is a planning date, not a booking.

Not ×7. A common veterinary sketch: first year ~15 human, second adds ~9, then ~5 per year. Giant breeds age faster; tiny ones slower. This is a conversation starter, not a lifespan forecast.

First year ~15, second ~9 more, then about 4 human years per cat year. Indoor cats often outlive the meme. Indoor/outdoor and dental care move this more than the formula.

I V X L C D M, subtractive pairs (IV, IX, XL…). MCMXCIX is 1999. Clocks that write IIII for 4 are being decorative. We stop at 3999; Unicode overlines for 4000+ are not this text box.

1–3999 using standard subtractive notation. 4 is IV, 9 is IX, 1999 is MCMXCIX. Super Bowl branding that writes Super Bowl 1 as I is the same system until they run out of Ms.

ITU Morse: letters, digits, slash for a space. SOS is ... --- ... Prosigns and punctuation beyond the alphabet are incomplete on purpose. This is a translator, not a ham-license course.

parseInt in one base, toString in another, 2–36. FF₁₆ is 255₁₀ is 11111111₂. Fractional nibbles and two’s-complement word size are not in the box. Leading zeros are dropped.

Any SI length prefix to any other, through the meter. Kilometer to millimeter, nanometer to picometer, yottameter to yoctometer — same 10³ steps the BIPM publishes. This is the 20-prefix grid for length, not 380 thin pages that all divide by a thousand.

Mass prefixes attach to the gram, not the kilogram. Kilogram is already kilo + gram. Scale yottagram down to yoctogram, or milligram to microgram, without mixing in pounds. Jewelry carats and troy ounces are separate legal pages.

Milliseconds, microseconds, nanoseconds, and the less-loved kilosecond all sit on the same second. A 250 ms camera shutter is 0.25 s. A CPU cycle in nanoseconds is still a second with nine zeros parked in front. Minutes and hours are sexagesimal, not SI prefixes — use those pages for 60-based time.

Audio A4 is 440 Hz. FM radio lives in megahertz. Wi-Fi and CPUs argue in gigahertz. IR spectroscopy climbs into terahertz. Same hertz, different zeros. This grid also covers millihertz if you are watching a very slow oscillator.

USB is 5 V. A thermocouple is millivolts. Transmission lines are kilovolts. Scope probes lie in between. Scale any SI voltage prefix to any other; this is not a voltage-drop calculator and does not know your transformer.

LED strings in milliamps, lab picoammeters, and utility kiloamperes share one ampere. A 20 mA loop is 0.02 A. Fuses are labeled in the prefix the catalog bought, not the one your meter displays.

Through-hole resistors print k and M. Shunts print milliohms. Insulation testers print gigaohms. Same ohm. Color bands still need a decoder; this page only moves the decimal.

A one-farad cap is a small brick. Everyday ceramics are picofarads and nanofarads; electrolytics are microfarads. Datasheets hop prefixes without warning. Convert before you order the wrong reel.

Power inductors are millihenrys. RF chokes are microhenrys. A 1 H inductor is an audio-era doorstop. Scale the prefix; this is not an impedance-at-frequency calculator.

Charge is current times time, but the unit still prefixes like the others. Battery milliamphours are a different dictionary (1 mAh = 3.6 C). Use this when a spec already wrote coulombs.

Magnetic flux in webers. Transformers and search-coil experiments still write milliwebers. Maxwells are a cgs cousin on a different page. Prefixes here stay SI.

Earth’s field is tens of microteslas. Fridge magnets are milliteslas. MRI is teslas. A 50 µT quiet-room reading is 0.05 mT. Gauss is 10⁻⁴ T — not a prefix, a different system.

Conductance is the reciprocal of resistance. Water-quality meters print microsiemens. A 1 mS reading is 0.001 S, which is a 1 kΩ equivalent if the geometry cooperates. This page only scales siemens.

Phone chargers in watts, homes in kilowatts, plants in megawatts, grids in gigawatts. A 1.5 kW kettle is 1,500 W. Terawatts show up in climate-scale diagrams, not in a breaker panel.

Food calories (thermochemical) are 4.184 J. Nutrition labels in kJ. Explosives data in MJ and GJ. Same joule. kWh and BTU are other dictionaries with their own pages.

A kilogram on Earth weighs about 9.8 N. Structural loads jump to kilonewtons. Rocket papers use meganewtons. Millinewtons show up in small-force sensors. Pounds-force is a different page.

Weather maps print hectopascals (same size as millibars). Tires in kilopascals. Hydraulics in megapascals. Material moduli in gigapascals. Standard atmosphere is 101,325 Pa = 101.325 kPa = 1,013.25 hPa.

Decimal SI (1,000) and binary IEC (1,024) in one grid. A drive sold as 1 TB (10¹² bytes) is about 0.909 TiB. A “1 GB” RAM stick is usually 1 GiB. Pick both dictionaries instead of arguing in a comment thread. Bits are not on this page — use bits to bytes first.

Type a character, a decimal code, 0x41, or U+1F600. You get the code point, hex, binary, and UTF-8 bytes. ASCII is 0–127. Everything else is Unicode. This is not an encoding converter for files — it is one scalar value at a time.

The international inch is exactly 25.4 mm. That 1959 agreement is why a 1/4 in bolt is 6.35 mm, not “about 6.” Use this when a US drawing meets a metric mill. Fractions of an inch still need you to divide the fraction first.

Gunter’s chain is 66 feet, which is 20.1168 m. Survey plats, cricket pitches (22 yards = 1 chain), and some railroad descriptions still use it. 80 chains make a mile. This is not an engineer’s 100 ft chain.

A rod (also perch or pole) is 16.5 ft = 5.0292 m. Four rods make a chain. Old US deeds stack rods, chains, and furlongs. If the deed says poles, it is this unit unless a local statute says otherwise.

The IAU 2012 astronomical unit is exactly 149,597,870,700 m — about 149.6 million km. Earth–Sun mean distance sits on that stick. Mars at 1.524 au is not a NASA press-round; it is that constant times 1.524.

A parsec is the distance at which 1 au subtends one arcsecond — about 3.26156 light years, or 3.085677581×10¹⁶ m. Proxima Centauri at ~1.3 pc is ~4.24 ly. Astronomy papers prefer parsecs; documentaries prefer light years.

A troy ounce is exactly 31.1034768 g. Bullion, coins, and lab reagents in precious metals use troy, not avoirdupois. A “1 oz gold coin” is 31.103 g, not the 28.35 g kitchen ounce. 12 troy ounces make a troy pound; that pound is not the grocery pound.

The metric carat is exactly 200 mg (0.2 g) since 1907. A 1 ct diamond is 200 mg. Jewelers still cut “points” (0.01 ct = 2 mg). This is not a gold-karat purity scale.

The UK (imperial) gallon is exactly 4.54609 L. The US liquid gallon is 3.785411784 L. A British 8-gallon beer firkin and a US 5-gallon bucket are not cousins. If the pump is in Canada or the UK, this is the gallon.

A metric cup is 250 mL. Australian and NZ recipes usually mean this. It is not the US customary cup (~236.588 mL) and not the US legal cup (240 mL) used on nutrition labels. If the cookbook is from Melbourne, start here.

US nutrition labels define a cup as 240 mL. That is a legal rounding of the customary 236.588 mL cup. FDA serving math uses 240. Grandma’s Pyrex may still be closer to 236.6. Know which dictionary the label used.

A PostScript pica is 12 points, and a point is 1/72 in. Six picas make an inch. InDesign’s “p6” is this pica. CSS px is a different conversation — use points to pixels if the output is a screen.

Desktop publishing locked the point at 1/72 of an international inch. 1 in = 72 pt. Letter paper 8.5 in is 612 pt. This is not 96 CSS px per inch and not a 300 DPI raster. For px, pick a DPI on the points-to-pixels page.

A twip is a twentieth of a point — 1/1440 of an inch. Word, VBA, and old Rich Text still size rows in twips. 1440 twips = 1 in. If a macro says 567, that is 28.35 pt, not a font size you type in the toolbar.

Divide minutes by 60. 90 minutes is 1.5 h, not 1.90 h. Timesheets that type 1.5 vs 1:30 are the same trap in reverse of the hours-to-minutes page.

Divide hours by 24. A 24 h clock-day, not a workday. 8 hours is 1/3 of a civil day. 168 hours is a week only because 7×24 — still this formula.

Divide days by 7. 14 days is 2 weeks. 30 days is about 4.286 weeks — a “30-day month” is not 4 weeks. ISO weeks are a numbering system; the length is still 7 days.

A decade is 10 years. The year on this site is the Julian year of 365.25 days used in astronomy, so a decade is 3,652.5 days, not “ten calendars plus guesswork.” History decades (1990s) are labels, not durations.

A millennium is 1,000 years. Again Julian: 365,250 days. Geology writes kyr and Ma; this page is the 1,000-year block, not carbon-date calibration.

A Julian year is 365.25 days × 86,400 s = 31,557,600 s. Light-years, orbital periods, and IAU constants use this, not 365 or 365.2425. A millisecond of a Julian year is still a lot of seconds if you expand it.

Divide by 365, ignoring leap days. Useful for “how many 365-day years is 1,000 days?” It is not a date calculator and will not land on a birthday. For leap years as 366-day blocks, use the sibling page.

A leap year calendar length is 366 days. Divide by 366 when someone asks how many leap-year-sized blocks fit in a span. 1,461 days is four Gregorian years including one leap day — 1,461/366 ≈ 3.99 of these blocks, which is why you should not use this as a date engine.

Sixty arcminutes in a degree. Survey bearings, astronomy declination, and map minutes all use this 60, not SI prefixes. 0.5° is 30′. A full turn is 21,600′.

3,600 arcseconds in a degree. Seeing of 1″, GPS, and IAU constants live here. 1/3600° is one arcsecond. Parallax of 1″ at 1 au defines the parsec.

A milliradian is 0.001 rad ≈ 0.057296°. Optics, ballistics “mils,” and some scopes use mrad. NATO mil is often 1/6400 of a circle (~0.98175 mrad) — not this SI milliradian. Read the reticle manual.

1 torr is 1/760 of a standard atmosphere = 101325/760 Pa ≈ 133.322 Pa. Vacuum gauges and older blood-pressure talk still say mmHg; torr and mmHg are treated as equal for this page. 760 torr is 101,325 Pa.

Weather: 1 hPa = 100 Pa = 1 millibar. Standard sea-level 1013.25 hPa is 101,325 Pa. A 850 hPa pressure surface is 85,000 Pa. METAR “Q1013” is this unit.

The International Table calorie is 4.1868 J. The thermochemical calorie on the other calories-to-joules page is 4.184 J. Steam tables and some older engineering texts use IT. Food “Calories” (kcal) are almost always thermochemical × 1,000, not IT.

Multiply kJ by 1,000. Nutrition labels in kJ, physics problems in J. A 4.184 kJ snack line is 4,184 J, which is 1 thermochemical kcal. The SI joule prefix tool also does mega and giga if the label jumps.

Divide newtons by 1,000. Structural notes write kN; lab load cells often write N. 9.81 N is about 1 kgf. 10,000 N is 10 kN — a small car’s weight-ish, depending on the planet.

1 PiB = 1,024⁵ bytes = 1,125,899,906,842,624 bytes. 1 PB = 10¹⁵ bytes. Multiply PiB by 1.125899906842624. Cloud “petabyte” quotes often mean PB; file-system df -h often means PiB. The SI vs IEC scaler does the rest of the ladder.

Divide kHz by 1,000. AM radio in kHz, FM in MHz. 440 kHz is 0.44 MHz. 2,400 kHz is 2.4 MHz — not 2.4 GHz Wi-Fi; that is another thousand. The SI hertz prefix tool covers GHz and THz in the same grid.

Convert JSON arrays of objects to CSV and CSV tables back to JSON entirely in your browser.

Convert XML documents to JSON and JSON structures back to XML with attribute mapping—all client-side.

Convert YAML configs to JSON and JSON payloads to YAML using a local js-yaml parser.

Switch spreadsheet exports between comma-separated and tab-separated formats in your browser.

Convert HTML snippets to Markdown and Markdown documents to HTML using Turndown and marked—client-side only.

Encode UTF-8 text to Base64 and decode Base64 back to text with the Web Encoding API.

Convert Java .properties files to JSON objects and flat JSON maps back to .properties format.

Convert PNG images to JPG and JPG photos to PNG in your browser with live preview and optional resizing.

Convert WEBP images to PNG and PNG graphics to WEBP with browser Canvas encoding and instant preview.

Convert iPhone HEIC/HEIF photos to JPG locally with preview, quality control, and optional resizing.

Rasterize SVG to PNG or wrap PNG in SVG—client-side with preview and resize controls.

Convert classic BMP bitmaps to PNG and PNG images to 24-bit BMP with preview and resize.

Extract PNG frames from ICO favicons or build multi-size ICO favicons from PNG—client-side with preview.

Convert TIFF scans to JPG and JPG photos to TIFF locally with preview, quality, and resize controls.

Extract plain text from PDFs or build multi-page PDFs from text—entirely in your browser with progress for large documents.

Combine images into a PDF or extract every PDF page as PNG/JPG images in a ZIP—with live progress.

Turn HTML or Markdown into multi-page PDFs in your browser using marked, html2canvas, and jsPDF.

Merge multiple PDFs into one or split a PDF into pages/ranges with progress bars and ZIP download for splits.

Extract MP3 audio from MP4 video or wrap MP3 into an MP4 container—locally with FFmpeg.wasm, WASM load UI, and live progress.

Convert WAV to MP3 and MP3 to WAV in the browser with FFmpeg.wasm, initialization UI, and live progress.

Convert QuickTime MOV to MP4 and MP4 to MOV with FFmpeg.wasm, WASM loading UI, and live progress.

Convert WebM to MP4 and MP4 to WebM in-browser with FFmpeg.wasm, initialization progress, and live encode percentage.

Convert OGG or FLAC audio to MP3 in your browser with FFmpeg.wasm, WASM load UI, and live progress.