UK solar guide
Solar panel cost calculator UK
Estimate UK solar panel system cost, annual electricity generation, bill savings, export tariff value, payback period and the number of panels needed.
Use the main calculator with UK inputs: pounds sterling, your supplier electricity rate, your Smart Export Guarantee or export tariff, and a realistic installed cost after any grant or discount. Start with the solar panel cost calculator, then use this page to check the UK-specific assumptions.
Open the solar panel cost calculatorUK assumptions to check
- Currency: use GBP and enter your own installed system cost.
- Electricity price: use your actual import rate per kWh from your energy supplier.
- Export tariff: enter your SEG or export payment rate rather than assuming exported solar has the same value as self-used solar.
- Solar output: UK solar generation varies by region, roof orientation, pitch and shading.
- Battery storage: a battery may increase self-consumption, but it should be compared against the extra installed cost.
How to use the calculator for the UK
Enter your annual or monthly electricity use from a recent bill, then set the electricity price field to your actual import tariff. The export tariff field should use your Smart Export Guarantee or supplier export rate. If you want payback based on out-of-pocket cost, enter the installed price after any discount, grant or VAT treatment that applies to your quote.
The solar panel output calculator is useful for testing different UK sunlight assumptions. Southern locations, unshaded roofs and good orientation normally produce more than shaded roofs or less favourable orientations. The peak sun hours guide explains why this input has a large effect on output.
Why UK payback varies
Solar payback in the UK depends heavily on how much generated electricity is used in the home. Self-consumed solar usually offsets the full import electricity price, while exported electricity is normally paid at a separate export tariff. Homes with daytime electricity use, EV charging, immersion diverters or batteries may consume more of their own solar generation.
For payback, compare the installation cost against the combined value of self-used solar and exported solar. The solar savings calculator and solar payback calculator help separate these two effects. For the exact formulas, see the methodology page.
UK solar calculator FAQs
What currency should I use?
Use pounds sterling. Enter the final installed system cost in GBP, especially if you want the payback period to reflect your actual out-of-pocket cost.
Should I use my import price or export tariff?
Use both, but in different fields. The electricity price field is for the import rate you pay. The export tariff field is for the rate paid on excess solar exported to the grid.
Does the calculator include UK grants automatically?
No. Enter the installed cost after any grant, discount or incentive if you want those items included in the payback calculation.
Is a battery included?
Only if you include the battery cost in the installed cost and adjust self-consumption accordingly. A battery can improve self-use, but it also raises the project cost.