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Solar Panel Output Calculator

Estimate daily solar energy in Wh and kWh from panel wattage, panel count, peak sun hours and a net performance factor.

1

Your inputs

Edit the example
Core inputs
W
panels
h/day

Equivalent full-sun hours for your location and season, not daylight hours.

Planning assumptions
%

One combined factor for modeled losses. Do not apply the same losses twice.

Example estimate · editable inputs

Estimated daily production

6.8 kWh/day

Daily energy
6,800 Wh/day
Rated array size
1,600 W

An average-day scenario, not guaranteed generation. Use seasonal peak sun hours and a combined loss factor.

BEHIND THE RESULT

How the calculation works

Daily Wh ≈ panel W × panel count × peak sun hours × net performance factor.

Peak sun hours express the day’s solar resource as equivalent hours at standard irradiance. Use a seasonal local estimate suited to your panel orientation.

A worked example

Four 400 W panels, 5 peak sun hours and an 85% net performance factor produce an estimate of 6,800 Wh/day, or 6.8 kWh/day.

What this estimate can’t tell you

Weather, shading, orientation, temperature, snow, controller and inverter behavior can change output. This is not a site-specific PVWatts simulation or guaranteed generation.

Sources & methodology

Formulas are derived from the units shown. Read our methodology or report a correction. Sources reviewed 2026-11-01.