Solar Panel Count Estimator
Estimate how many solar panels meet an energy target.
Calculate solar panel count estimator from clear inputs
Solar Panel Count Estimator gives a focused worksheet for home & diy questions where a quick deterministic estimate is more useful than a spreadsheet. The solar panel count estimator fields mirror the variables in its formula, and the output separates the main result from supporting values so you can sanity-check this calculation before reusing it.
900 monthly kWh with 4.5 sun hours, 400 W panels, and 80 percent efficiency needs 21 panels.
Keep the estimate private in your browser
For Solar Panel Count Estimator, every calculation runs in your browser with no upload, account, cookie, live lookup, or server-side storage. The solar panel count estimator result is best treated as a planning number because the real-world constraints behind this estimate can change the answer. Adjust the solar panel count estimator assumptions and confirm important decisions against the relevant source of truth for that exact situation.
Frequently Asked Questions
How is the panel count calculated?
Monthly kWh ÷ 30 gives the daily target, and each panel makes sun hours × panel watts × efficiency. 900 kWh a month with 4.5 sun hours, 400 W panels, and 80% efficiency needs 21 panels.
What are peak sun hours?
The number of hours per day when sunlight averages 1,000 W per square meter. Typical US values run from about 3.5 in cloudy northern areas to 6 or more in the Southwest; NREL's PVWatts tool gives local figures.
What efficiency percentage should I use?
About 75 to 85% covers inverter losses, wiring, heat, and dirt. The default 80% is a common planning figure.
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