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
- Caravan & Motorhome Solar CalculatorFree UK caravan solar calculator: enter daily Wh, peak sun hours and battery type — get panel wattage, leisure battery Ah, MPPT controller and inverter size for touring caravans and motorhomes.
- 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.
- Solar Export Tariff (SEG) CalculatorCalculate your annual Smart Export Guarantee revenue. Free 2026 calculator with Octopus Outgoing 15p, E.ON Next Export 16.5p, EDF SEG 5.6p, and OVO Smart Export Plus rates.
- Solar Panel Replacement Cost Calculator (UK)Free UK solar panel replacement cost calculator. Work out labour, materials, MCS recycling and call-out costs and compare against a full new MCS install.
- 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.
- Hybrid Solar System CalculatorSize a hybrid PV and battery system for UK homes: array kWp, usable battery kWh, hybrid inverter rating, and SEG export. MCS-aligned defaults.
- 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.
- SEG Net Export Savings Calculator (UK)Calculate your annual electricity bill savings under the UK Smart Export Guarantee (SEG). Compares Octopus Outgoing, E.ON Next Export, OVO, EDF and British Gas tariffs.