☀️ Solar Panel Wattage Calculator
Estimate the total solar panel wattage and panel count needed to cover your daily electricity usage, based on your local sun hours.
How solar array sizing works
To size a solar power system, you need to cover your daily electricity use even though the sun only shines effectively for a few hours a day. This calculator divides your daily energy use by your location’s average peak sun hours (the number of hours of standard, full-intensity sunlight equivalent per day), then adjusts upward to account for real-world system losses from wiring, inverter conversion, temperature, and dust.
The formula
Required array wattage = (daily kWh × 1000) ÷ peak sun hours ÷ (1 − system loss %). The number of panels is that wattage divided by the wattage rating of a single panel, rounded up.
Peak sun hours vary by location and season (roughly 3-4 in cloudier climates, 5-7 in sunny ones); check a local solar irradiance map for an accurate figure. This tool gives a general planning estimate only and does not replace a site assessment from a qualified solar installer.