Solar electricity calculator
Power × peak sun hours × performance ratio. Change the region to swap the default sun hours.
Defaults to your region. Switch to compare any other scale.
Result
20.25 kWh
Daily yield
- Yearly yield7,391 kWh
- Gross annual value1,183
- PSH used4.5
Site matters more than the average
NREL PVWatts and similar tools use weather files, tilt, and azimuth. This page is the envelope math for first sizing.
Formula
Daily kWh = kW × peak sun hours × PRYear ≈ daily × 365PR defaults to 0.75 (dust, heat, inverter)
How it is calculated
- Enter DC system size in kW.
- Peak sun hours default to the selected region — override if you have a local figure.
- Apply a performance ratio (0.75 is a conservative default).
Questions
What is a peak sun hour?
One hour of 1,000 W/m² irradiance. Five PSH means the day’s energy equals five hours at peak sun, not five hours of clock time.