Free Solar Calculators That Actually Work
Get instant, accurate answers on panel tilt angle, system sizing, voltage, wire gauge, and installation cost. No signup, no email — just numbers. Built for UK homeowners and DIY installers.
Most popular calculators
- How Many Solar Panels Do I Need?Free UK calculator to estimate how many solar panels your home needs. Uses MCS-aligned irradiance, average British household consumption (2,700 kWh/yr), and 400 W panel specs.
- EV Charging Calculator (UK)Free EV charging calculator for UK drivers. Estimate kWh drawn, charge time on a 7 kW home wallbox, electricity cost at 2026 Ofgem cap rates, and the savings if you charge from solar PV.
- Off-Grid Solar System Calculator (UK)Free UK off-grid solar calculator. Sizes PV array (kWp), battery bank (kWh), and inverter (kW) from daily kWh load using PVGIS irradiance data and MCS-aligned design factors.
- Solar Investment Tax Credit Calculator (UK)Free commercial solar investment tax credit calculator for UK businesses. Estimate your Annual Investment Allowance (AIA), 50% First-Year Allowance, Smart Export Guarantee tariff, and net cost after every business incentive.
- Solar Panel Savings Calculator (UK)Free solar panel savings calculator for UK homes. Estimate 25-year lifetime savings using your annual generation, Ofgem tariff cap rate, SEG export tariff, self-consumption rate, and price escalation.
- Cost of Solar Panels Calculator (UK)Free UK solar panel cost calculator. Estimate installed cost from your monthly kWh, peak sun hours, £/W price, and the 0% VAT relief. 2026 MCS, Energy Saving Trust and Solar Energy UK data.
- EV Charging Cost Calculator (UK)UK EV charging cost calculator using April 2026 Ofgem cap rates and Octopus Intelligent Go off-peak tariffs. Per-session and annual running cost on a 7 kW wallbox plus solar PV offset.
- Solar Panel Output Calculator (UK)Free UK solar panel output calculator. Estimate daily, monthly, and 25-year kWh production from your array, sun hours, and system efficiency — plus pound savings.
- Solar Panel Tax Relief & Grant CalculatorFree solar tax relief and grant calculator for UK homeowners. Estimate the value of 0% VAT (HMRC Notice 708/6), ECO4, HUG2, and council grants on your domestic solar installation.