Solar panel payback calculator
Real solar payback for your roof, region and tariff
This is a free UK calculator. Enter your figures to get an instant, personalised result — no signup, no email capture, no upsell.
Frequently asked questions
How long does solar take to pay back?
Typically 7–11 years on a south-facing UK roof at current install costs (~£6–9k for 4kWp). East/west orientations add 1–2 years.
Do solar panels still work without sun?
Yes — UK panels still generate ~10–20% of peak on overcast days. Annual figures bake in cloud cover for your region.
Should I add a battery?
It pushes self-consumption from ~30% to ~65%, materially shortening payback. Use the combined ROI tool to model both together.