Solar Production Calculator
Estimate how many kWh solar panels make per year, month and day where you live.
Your result
Enter your numbers and press the button. Your result appears here.
Production estimates here use NREL PVWatts results for a south-facing roof at a 20° tilt with 14% system losses. Pick your state to load its figure.
How it works
Yearly kWh = system kW × yearly kWh per kW. Monthly = yearly ÷ 12; daily = yearly ÷ 365.
Example: 8.00 kW makes about 10,936 kWh a year, 911 a month and 30.0 a day.
At a glance
Same settings as the calculator, changing only the system size.
| System size | Per year | Per month | Per day |
|---|---|---|---|
| 4 kW | 5,468 kWh | 456 kWh | 15.0 kWh |
| 6 kW | 8,202 kWh | 684 kWh | 22.5 kWh |
| 8 kW | 10,936 kWh | 911 kWh | 30.0 kWh |
| 10 kW | 13,670 kWh | 1,139 kWh | 37.5 kWh |
| 12 kW | 16,404 kWh | 1,367 kWh | 44.9 kWh |
| 15 kW | 20,505 kWh | 1,709 kWh | 56.2 kWh |
Common questions
How much electricity does a solar panel produce?
A 400 W panel makes about 550 kWh a year, or 1.5 kWh a day, at the U.S. average of 1,367 kWh per kW. In Arizona it is closer to 700 kWh a year.
Why is my output lower in winter?
Shorter days, a lower sun and snow cut production. The yearly figure averages the seasons.
Sources
- NREL PVWatts v8 (20° tilt, south-facing, 14% losses), state results compiled by TheGreenWatt: https://thegreenwatt.com/average-peak-sun-hours-by-state/
- NREL PVWatts Calculator: https://pvwatts.nrel.gov/