How do I find my kWh usage?

From your electricity bill, or enter the bill amount and we'll estimate the kWh.

What are peak sun hours?

The daily average of full-irradiance hours. We default to the capital's value.

It's a rough estimate. Installation needs an engineering survey of roof, shading, and orientation.

Peak sun hours genuinely vary between countries and cities.

No, the calculation is entirely local.

Estimate required system size, panel count, and roof area.

Practical calculatorGeneral editable assumptionsGlobal-readyInteractive chart

Last updated: 2026-05-16

This calculator uses generic assumptions. Use advanced mode to override them for a more accurate result.

Source: default

kW = Daily kWh / (Sun hours × Performance Ratio)

How do I find my kWh usage?: From your electricity bill, or enter the bill amount and we'll estimate the kWh.
What are peak sun hours?: The daily average of full-irradiance hours. We default to the capital's value.
Is the result accurate?: It's a rough estimate. Installation needs an engineering survey of roof, shading, and orientation.
Why do numbers differ by country?: Peak sun hours genuinely vary between countries and cities.
Do you store my data?: No, the calculation is entirely local.

Results are estimates and not professional advice. Verify important decisions with a qualified professional.