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Solar panel calculator (UK)

UK solar pays in two ways: every kWh you use yourself saves the 26.32p cap rate, and every kWh you export earns your supplier's export rate, usually far less. This calculator splits the two, uses official regional installation costs, and shows payback for each region.

Your region

Fills in solar output and, where official data exists, the regional installed cost.

Electricity you use per year (kWh)

From your bills or supplier app.

System size (kW)

Solar production (kWh per kW per year)

Installed price (£ per kW)

Electricity price (p/kWh)

Export payment (p/kWh)

What your supplier pays for each kWh you send to the grid.

Share of solar used at home (%)

Higher if someone is home in the day or you have a battery; lower if the house is empty while the sun is up.

Grants or discounts (£)

Electricity price increase (% per year)

Years to compare

Your solar estimate

Solar generated in year 1: 3,916 kWh
Used at home: 1,566 kWh
Exported: 2,350 kWh
Share of your use covered: 58%
Bill saving in year 1: £412
Export income in year 1: £282
Total benefit in year 1: £694
Installed cost after grants: £6,380
Payback: 9 years
Net gain over 25 years: £12,640

Estimates only. Panel output falls 0.5% a year and electricity prices rise at the rate you set; export rates are held flat. Your quote, roof and tariff decide the real result.

Solar payback by region

Region	Cost per kW	kWh per kW	Payback
South East	£1,859	1,156	9.1 yrs
East of England	£1,796	1,041	9.7 yrs
Wales	£1,838	1,042	9.9 yrs
West Midlands	£1,778	968	10.4 yrs
South West	£1,887	1,023	10.4 yrs
North East	£1,760	949	10.5 yrs
East Midlands	£1,840	979	10.6 yrs
Yorkshire and The Humber	£1,800	952	10.7 yrs
North West	£1,800	886	11.5 yrs
Scotland	£1,767	859	11.6 yrs
London	£2,101	1,019	11.6 yrs

Simple payback using each region's DESNZ mean cost for 0-4 kW systems (2025/26), PVGIS output, 26.32p/kWh for the 40% used at home and 12p/kWh for the 60% exported. Change the split above to match your home.

Defaults and sources

Electricity price: 26.32p/kWh and 54.83p/day standing charge: Ofgem price cap GB average, Direct Debit, 1 October to 31 December 2026 (no VAT on electricity this period)Ofgem, Energy price cap unit rates and standing charges · checked Oct 27, 2026
Solar production per kW: Modelled for one city in each regionPVGIS 5.3 (European Commission JRC): south-facing, 35 degree tilt, 14% system losses, SARAH-3 satellite data · checked Oct 27, 2026
Installed solar cost: Median £1,595/kW (0-4 kW) and £1,546/kW (4-10 kW) in 2025/26; regional means are used when you pick a regionDESNZ Solar PV cost data, May 2026 (MCS installations, total installed capacity basis, official statistics in development) · checked Oct 27, 2026
Export payment (Smart Export Guarantee): Set by each supplier. Example default: Outgoing Octopus pays 12p/kWh (variable rate, Octopus import customers with a smart meter)Octopus Energy, Outgoing Octopus; Ofgem SEG annual report lists 50 tariffs from 11 suppliers in 2024/25 · checked Oct 27, 2026
VAT on solar panels and batteries: 0% on installation in homes in Great Britain from 1 May 2023 to 31 March 2027 (batteries, including retrofitted and standalone, from 1 February 2024); 5% from 1 April 2027HMRC VAT Notice 708/6, Energy-saving materials and heating equipment · checked Oct 27, 2026

How the calculator works

Generation is your system size times your region's PVGIS output per kW. The share you use at home saves your import price; the rest is exported and earns your export rate. Your annual use caps the home share.

Installed cost is size times price per kW, minus any grant. Payback is the first year cumulative savings cover the cost, with panel output falling 0.5% a year and the import price rising at the rate you set.

Solar in the UK: common questions

How much do solar panels cost in the UK in 2026?

DESNZ's official statistics put the median installed cost at £1,595 per kW for 0-4 kW systems in 2025/26, about £6,380 for a 4 kW system. Regional means range from about £1,760 per kW in the North East to £2,100 in London.

Is VAT charged on solar panels in the UK?

No, until 31 March 2027: HMRC zero-rates the installation of solar panels and batteries in homes in Great Britain. It reverts to 5% from 1 April 2027.

How much can I earn from exporting solar power?

It depends on your supplier's Smart Export Guarantee tariff. Ofgem counted 50 SEG tariffs from 11 suppliers in 2024/25; Outgoing Octopus, for example, pays 12p/kWh to its import customers. A 4 kW system exporting 60% of about 4,000 kWh earns roughly £290 a year at 12p.

What is the payback period for solar panels in the UK?

At the 2025/26 median cost, using 40% of the output at home and exporting the rest at 12p, a 4 kW system in London pays back in about 9-12 years depending on installer price. A battery or daytime use raises the home share and shortens it.