Solar panel calculator
Work out how much electricity solar panels would make on your home each year, and what that is worth.
Solar output from PVGIS (European Commission), checked 13 November 2026.
Result
4 kWp of panels tilted at 35°, facing south in Birmingham, would make about 3,872 kWh a year. If you used all of it as it is made, that is worth £1,019 a year at the price cap rate of 26.32p per kWh.
kWh a year
| Used in the home | 3,872 kWh |
|---|---|
| Worth a year | £1,019 |
Month by month:
Show the workings
| Step | Sum | Answer |
|---|---|---|
| Electricity made in a year | 968 kWh per kWp × 4 kWp | 3,872 kWh |
| Used in the home as it is made | 3,872 kWh × 100% | 3,872 kWh |
| Worth, at the unit rate | 3,872 kWh × 26.32p | £1,019 |
What this leaves out or assumes
- PVGIS's long-run average for the place, so a sunny or dull year will differ. Shade from trees or buildings is not counted.
- Electricity that is not used as it is made goes to the grid; no payment for it is counted here.
Where the figures come from
- PVGIS output from 1 kWp in Birmingham, tilted at 35°, facing south: 968 kWh per kWp. Source: PVGIS 5.3, European Commission Joint Research Centre. Checked 13 November 2026.
- Electricity unit rate, price cap, Great Britain average, Direct Debit: 26.32p per kWh. Source: Ofgem: Energy price cap unit rates and standing charges. Checked 13 November 2026.
How solar output is worked out
Solar panels are rated in kilowatts peak (kWp): their output in full sun. What they make in a year depends on the sunshine where you live, the tilt and the way they face. PVGIS, the European Commission's solar model, gives the yearly output from 1 kWp for each UK council area. Multiply it by your system's size to get your yearly output.
What it is worth
Electricity you use as it is made saves buying it at your unit rate. A battery, or running appliances in the day, lets you use more of it. Electricity sent to the grid may earn a payment under an export tariff under Ofgem's SEG scheme, which this calculator does not count. The Warm Homes guide covers government help with solar.
Output comes from PVGIS with its standard allowance of 14% for losses, for the centre of each council area. Shade is not counted. This gives information, not advice.