How long until your solar panels actually pay for themselves?
Drop in your kWh use, electricity rate, and system size. Get the real payback period, 25-year savings, ROI, and CO2 avoided. Updated for 2026 with US ITC, UK SEG, AU STC, DE EEG.
Cost breakdown
Year-by-year cash flow
| Year | Production | Self-use savings | Export revenue | Cumulative net |
|---|---|---|---|---|
| 1 | 12,000 kWh | $1428.00 | $288.00 | $-15084.00 |
| 5 | 11,762 kWh | $1606.13 | $282.28 | $-7795.53 |
| 10 | 11,471 kWh | $1860.37 | $275.30 | $2373.29 |
| 15 | 11,187 kWh | $2154.85 | $268.48 | $13897.23 |
| 20 | 10,910 kWh | $2495.94 | $261.84 | $26997.10 |
| 25 | 10,640 kWh | $2891.02 | $255.36 | $41928.48 |
Assumes: 0.5% annual degradation, 25 year life.
How the math works
The math is simple. Net out-of-pocket = gross install cost minus incentive. Each year, panels produce a bit less (0.5% degradation), and electricity gets a bit pricier (rate inflation). You save what you avoid buying from the grid, plus you earn back what you export. Payback is the year your cumulative savings cross zero.
- 1Pick your countryLoads sensible defaults for cost per watt, electricity rate, production factor, and the local incentive program.
- 2Enter system sizeMost US homes pick 6–10 kW. Larger if you have heat pumps or an EV.
- 3Confirm electricity rateUse your last bill. Average rate per kWh, including delivery.
- 4Adjust incentiveDefault loads. Tweak if you have state rebates or utility credits.
- 5Read the barShorter bar = faster payback out of the 25-year panel warranty.
What is solar payback?
Solar payback period is the number of years before the cash you save on electricity bills (plus what you earn from exporting surplus power) equals what you actually paid out of pocket for the panels.
In 2026 the US median residential payback runs about 7–10 years thanks to the 30% federal ITC. Australia is closer to 4–6 years because hardware is cheap and sun is abundant. Germany sits around 9–12 years. The UK is 8–11 years with SEG export tariffs in the mix. Korea and Japan vary widely with local subsidies.
Three numbers move payback the most: cost per watt, your electricity rate, and how much sun your roof actually gets (the production factor). Incentives push the curve forward; rate inflation makes future savings worth more.
Solar payback questions, answered
Solar payback explained
Plain-English breakdowns of incentives, panel choices, and ROI math.