Estimate only — payback and ROI use the rate, incentives and production you enter, with no live pricing data.
About this tool
Solar Payback & ROI Calculator is a free, in-browser tool that estimates how long a solar system takes to pay for itself and its 25-year return. It reports the net cost after incentives, your annual electricity savings, the payback period in years, the lifetime net savings and the return on investment.
Net cost is system cost − incentives (rebates and tax credits). Annual savings is production × electricity rate — the value of the kWh you no longer buy. Payback is net cost ÷ annual savings, and over a 25-year panel warranty the net savings are (annual savings × 25) − net cost, with ROI% = net savings ÷ net cost × 100.
Use it to compare quotes or decide whether solar pencils out for you: adjust the electricity rate to your utility's price and the incentives to your local programs, and watch payback and ROI update live. All math runs in your browser and nothing is uploaded.
Frequently asked questions
What counts as an incentive?
Any one-time reduction to the up-front price: federal or national tax credits, state rebates, utility incentives. Subtract them from the system cost to get the net cost the payback is measured against.
Where do I get the annual production figure?
From an installer's estimate or a solar production tool for your location and array size (roughly system kW × peak sun hours × 365 × derate). Enter the kWh your panels are expected to generate per year.
Does this account for rising electricity prices or panel degradation?
No — it uses a flat rate and flat production for a clear, conservative baseline. In reality utility rates tend to rise (shortening payback) while output degrades slowly (lengthening it); the two partly cancel out.
Are these results a guarantee?
No. They are estimates based entirely on the figures you enter — rate, incentives and production are user-supplied, with no live pricing data. Treat the output as a planning guide, not a financial promise. Everything is computed locally.
More tools