Solar System Size Calculator
Estimate the solar array size and number of panels your home needs.
kWh
h
%
W
How it works
Array size (kW) = daily use ÷ (peak sun hours × (1 − losses)). Peak sun hours are the equivalent hours of full-strength sunlight your location gets per day. The panel count is rounded up so the array covers your use. Shading, roof angle, and seasons change real output, so treat this as a first estimate. Example: with the default values, required array size comes to 3.33 kW.
FAQ
Is this calculator free?
Yes. No signup is needed and nothing you enter is stored.
Is the result exact?
Results are rounded for display. For financial, medical, or legal decisions, confirm with a professional.
Do my numbers leave my device?
No. The calculation runs in your browser.