Solar system size in kW, number of panels, roof space, cost and payback from your monthly units.
How this works
Daily use = monthly kWh / 30. System kW = daily kWh / (peak sun hours x (1 – losses)). Pakistan and India get about 5 to 6 sun hours, the Gulf 6, the UK 2.5. A 585 W panel needs about 3 m² of roof including gaps.
Questions people ask
How do I use the Solar System Size tool?
Fill in the fields, starting with “Monthly use”, “Peak sun hours” and “Panel size”, and change any other options that match your home. The answer, a drawing and practical tips update as you type, and the Copy link button saves your numbers in a link you can share.
Is the Solar System Size tool free?
Yes. The Solar System Size tool is free, with no sign-up, and works on phones, tablets and computers. The results are estimates to help you plan, so check with a qualified professional before structural, electrical, gas or plumbing work.