Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Unit Converters
Solar Panel Output: Sun Hours to Daily kWh
kWh/day = kW × peak sun hours (STC-ish, no derate).
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.
Array watts
W → kWh
1.8 kWh
Peak-sun-hours, not clock hours. Dirt, heat, and inverter loss are not in the slider.
- Array
- 400 W
- Sun hours
- 4.5
Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
Array watts
The “Array watts” value used in this tool’s formula. Adjust it to see results update live.
Peak sun hours
The “Peak sun hours” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
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. kWh/day = kW × peak sun hours (STC-ish, no derate). Example: 400 W × 4.5 h → 1.8 kWh. 6 kW array × 5 h → 30 kWh before losses.
kWh/day = kW × peak sun hours (STC-ish, no derate).
Example: 400 W × 4.5 h → 1.8 kWh. 6 kW array × 5 h → 30 kWh before losses.
When to use this Solar Panel Daily kWh
Common use cases
- 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.
- Sanity-check with this case: 400 W × 4.5 h → 1.8 kWh. 6 kW array × 5 h → 30 kWh before losses.
- The relationship is: kWh/day = kW × peak sun hours (STC-ish, no derate).
Localized examples
- Unit Converters: the example on this page uses the same formula as the widget.
What you get
- Fields: Array watts, Peak sun hours
- kWh/day = kW × peak sun hours (STC-ish, no derate).
- Example on the page: 400 W × 4.5 h → 1.8 kWh. 6 kW array × 5 h → 30 kWh before losses.
How to Convert Solar Panel Daily kWh Step-by-Step
- 1Enter Array watts, Peak sun hours. Use the values you have, not a catalog average, unless that is all you know.
- 2kWh/day = kW × peak sun hours (STC-ish, no derate).
- 3Worked case: 400 W × 4.5 h → 1.8 kWh. 6 kW array × 5 h → 30 kWh before losses.
- 4Check which dictionary the other person is using — US or UK, decimal or 1,024 — then trust the number.
Governing formula
kWh/day = kW × peak sun hours (STC-ish, no derate).
400 W × 4.5 h → 1.8 kWh. 6 kW array × 5 h → 30 kWh before losses.
Example: set Array watts = 400, Peak sun hours = 4.5, then read the result.
Variable definitions
- value
Array watts
The “Array watts” field. Default 400; typical range 10–20000.
- sunHours
Peak sun hours
The “Peak sun hours” field. Default 4.5; typical range 1–8.
- The conversion (kWh/day = kW × peak sun hours (STC-ish, no derate).) does not pick US vs UK gallons, SI vs binary megabytes, or Mach at altitude for you. Read the footnote on the page.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Multiply by ~0.8 for a first-year rooftop guess.
Related calculators
Unit Converters
- Watts and Hours to kWhkWh = 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.
- Appliance Running CostCost = 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.
- BTU to kWhUS 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).
- kWh to MegajoulesYour 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.
- SI Joule Prefix ConverterFood 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.
- SI Watt Prefix ConverterPhone 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.
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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.
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