Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Electronics & Hardware Engineering
PC PSU Wattage Calculator — Desktop Power Supply Sizing
Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom.
Size a desktop PSU from CPU, GPU, and system component power draw. Planning estimates only — verify with production tools and vendor pricing where applicable.
Inputs
15350
0600
50300
20100
Smart analysis
Recommendations
Tailored to your live inputs and result—guidance only, not professional advice.
- Interpret
Treat this as a planning estimate
Primary result: Recommended PSU = 550 W. Re-run with optimistic and pessimistic inputs to understand the range—not just a single point.
Scenario studio
Compare A vs B
Capture two sets of inputs on this device, then see which outcome wins. Share either scenario with a link.
Scenario A
Adjust inputs, then capture this slot.
Scenario B
Adjust inputs, then capture this slot.
Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
CPU TDP (W)
The “CPU TDP (W)” value used in this tool’s formula. Adjust it to see results update live.
GPU TDP (W)
The “GPU TDP (W)” value used in this tool’s formula. Adjust it to see results update live.
Other components (W)
The “Other components (W)” value used in this tool’s formula. Adjust it to see results update live.
Headroom (%)
The “Headroom (%)” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
Size a desktop PSU from CPU, GPU, and system component power draw. Planning estimates only — verify with production tools and vendor pricing where applicable. Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom. Example: 65 W CPU + 200 W GPU + 100 W system → 365 W; recommend 550 W PSU (50% headroom).
Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom.
Example: 65 W CPU + 200 W GPU + 100 W system → 365 W; recommend 550 W PSU (50% headroom).
When to use this Power Supply (PSU) Wattage
Common use cases
- Size a desktop PSU from CPU, GPU, and system component power draw.
- Sanity-check with this case: 65 W CPU + 200 W GPU + 100 W system → 365 W; recommend 550 W PSU (50% headroom).
- The relationship is: Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom.
Localized examples
- Electronics & Hardware Engineering: the example on this page uses the same formula as the widget.
What you get
- Fields: CPU TDP (W), GPU TDP (W), Other components (W), Headroom (%)
- Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom.
- Example on the page: 65 W CPU + 200 W GPU + 100 W system → 365 W; recommend 550 W PSU (50% headroom).
How to Calculate Power Supply (PSU) Wattage Step-by-Step
- 1Enter CPU TDP (W), GPU TDP (W), Other components (W), then the remaining fields. Use the values you have, not a catalog average, unless that is all you know.
- 2Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom.
- 3Worked case: 65 W CPU + 200 W GPU + 100 W system → 365 W; recommend 550 W PSU (50% headroom).
- 4Compare the result to last month’s invoice or a vendor calculator before you commit capacity.
Governing formula
Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom.
65 W CPU + 200 W GPU + 100 W system → 365 W; recommend 550 W PSU (50% headroom).
Example: set CPU TDP (W) = 65, GPU TDP (W) = 200, Other components (W) = 100, then read the result.
Variable definitions
- cpuTdp
CPU TDP (W)
The “CPU TDP (W)” field. Default 65; typical range 15–350.
- gpuTdp
GPU TDP (W)
The “GPU TDP (W)” field. Default 200; typical range 0–600.
- systemOverheadW
Other components (W)
The “Other components (W)” field. Default 100; typical range 50–300.
- headroomPct
Headroom (%)
The “Headroom (%)” field. Default 50; typical range 20–100.
- Closed-form math (Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom.) misses idle time, egress, packet loss, and reserved capacity on the real bill.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Total W = CPU TDP + GPU TDP + motherboard/RAM/storage (~100 W) × headroom.
Related calculators
Electronics & Hardware Engineering
- Decibel (dB) to Watt/Volt ConverterConvert dB to power and voltage ratios relative to a reference.
- LED Resistance CalculatorFind the series resistor value for a given supply voltage and LED forward voltage.
- Ohm's Law CalculatorSolve for voltage, current, resistance, and power in DC circuits.
- Battery Life / Runtime EstimatorCalculate how many hours a battery will run at a given load current.
- Capacitor RC Time Constant CalculatorCompute RC time constant and capacitor charge times.
- PCB Trace Width CalculatorEstimate PCB trace width needed to carry a given current safely.
Get a note when we add a planner
Occasional email when something new is worth opening. We never share your address. Unsubscribe anytime.
Discover & search
Explore More Tools
Related tools in Electronics & Hardware Engineering — strengthening topical internal links.
Same category · 3 tools
Browse all →Resistor Color Code Calculator
Electronics & Hardware Engineering
Decode 4-band resistor color codes into resistance in ohms.
Ohm's Law Calculator
Electronics & Hardware Engineering
Solve for voltage, current, resistance, and power in DC circuits.
LED Resistance Calculator
Electronics & Hardware Engineering
Find the series resistor value for a given supply voltage and LED forward voltage.
Community
Reviews & Ratings
See what others think about this tool, then leave your own rating to help improve CalculioHub.
4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
Improve this tool
Suggestion Box
Share an idea, report a bug, or send general feedback for Power Supply (PSU) Wattage Calculator. Your input helps shape what we build next.