Free solar calculators for clearer home energy decisions.
Estimate solar panel savings, payback time, system size, battery storage and electricity costs before you compare quotes or commit to a project.
Start with the number behind your decision.
Each free solar calculator answers a different question. Use one focused tool or move between them as your project becomes clearer.
Solar Savings Calculator
Estimate annual bill savings, export income, solar payback and 25-year return using your electricity use, tariff, installation cost and system assumptions.
Calculate solar panel savings →Solar Payback Calculator
Compare cash and finance scenarios, maintenance, interest and long-term return to estimate your solar break-even point.
Calculate solar payback →Solar System Size Calculator
Estimate solar system capacity, panel count, annual generation and roof area from your electricity demand and planning assumptions.
Estimate solar system size →Battery Storage Calculator
Estimate battery capacity for evening electricity use or essential backup without confusing battery size with solar panel capacity.
Estimate battery capacity →Electricity Cost Calculator
Calculate appliance running costs with day and night tariffs, power consumption and usage time.
Calculate electricity cost →How to use SolarWorth before requesting a quote
Online solar estimates are most useful when they show the assumptions behind the answer. SolarWorth helps you build a baseline you can compare with installer projections.
Start with your real energy use
Use recent electricity bills where possible. Annual consumption, tariff and usage patterns shape system sizing and savings estimates.
Test more than one scenario
Change installation cost, solar yield, self-consumption, export payments or finance assumptions to see which inputs drive the result.
Compare the estimate with quotes
Ask why an installer forecast differs. Roof orientation, shading, system losses, equipment and local tariffs can all change the outcome.
Are solar panels worth it for your home?
There is no universal answer. Solar value depends on the installed price, annual solar generation, electricity tariff, export payment and how much generated electricity you use directly in the home.
A lower quote does not automatically mean a better return, and a large system does not automatically create the highest savings. The useful comparison is between net cost and realistic annual benefit over time.
Use the solar panel savings calculator for the broad financial picture, then use the solar payback calculator to examine the break-even point in more detail.
Build a clearer solar estimate, one question at a time.
Solar projects connect several decisions. A system-size estimate affects expected generation. Generation and self-consumption affect savings. Battery capacity can change when electricity is used, but it also changes total project cost.
How long do solar panels take to pay for themselves?
Learn how the solar panel payback period is calculated, which assumptions change the result and how to compare quotes without relying on one optimistic headline number.
Read the solar payback guide →Free solar calculator FAQs
What can I calculate with SolarWorth?
You can estimate solar panel savings, payback period, system size, panel count, battery storage capacity and appliance electricity costs.
Which solar calculator should I use first?
Start with the Solar Savings Calculator for a broad estimate of savings and long-term return. Use the dedicated payback, system size or battery calculators when you need a more focused result.
Are the SolarWorth calculators free?
Yes. They are free to use and do not require an installer quote request or sales form.
How accurate are online solar calculators?
They are planning estimates. Results improve when you use accurate electricity consumption, tariffs, installation cost and location-based solar production assumptions. Actual performance also depends on shading, roof orientation, equipment, system losses and household usage.
Do these estimates replace a professional solar assessment?
No. A professional assessment is still needed for roof condition, structural suitability, shading, electrical design, equipment selection, permits and local requirements.
SolarWorth provides independent planning estimates only. Results are not engineering, installation, legal, tax or financial advice.