Free Solar Panel Calculators
Six free solar tools — size your system, calculate payback, estimate export earnings, model your battery ROI, and check your UK grant eligibility.
Solar Panel Size Estimator
Find out how many solar panels your home needs based on your electricity usage and location.
kWh-based sizingSolar Payback Calculator
Calculate how many years until your solar system pays for itself, including incentives and net metering.
Includes tax creditsSEG & Feed-in Tariff Calculator
Calculate how much you can earn by exporting surplus solar electricity. Covers UK SEG rates and Australian feed-in tariffs by state.
UK + AustraliaUK Solar Grant Eligibility Checker
Answer 6 questions to find out which UK solar grants you qualify for — ECO4, Warm Homes Plan, 0% VAT, SEG, and more.
Free eligibility checkUK Solar Savings Calculator
See your annual bill savings, SEG income, and payback period based on your region, system size, and self-consumption rate.
Region-specific yieldsSolar Battery Storage ROI Calculator
Find out whether a home battery is worth the investment — modelled against UK import and SEG rates with preset battery options.
Includes Tesla PowerwallECO4, Warm Homes Plan, and other schemes can fund solar panels at no cost. Use our grant eligibility checker or browse all UK solar grants.
About these estimates
Solar sizing depends heavily on your local peak sun hours, roof orientation, shading, and specific panel model. These calculators give you a ballpark figure to start a conversation with installers — not a substitute for a professional site assessment. Always get at least 2–3 quotes.
Sources: NREL, SEIA, EnergySage marketplace data (2025–2026).