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Calculators / Solar payback calculator

How long until solar pays for itself?

Payback is the year the running total of what you save reaches what you paid. The curve below shows every year of it, not just the crossing.

The four numbers that decide payback

In order of how much they move the answer for a typical household:

What your utility pays for exports
Under full net metering a kilowatt-hour you send out is worth one you take back. Under an export rate set at a fraction of retail, only the electricity you consume as you generate it is worth full price. That single ratio can add years. It is listed under the results, with the tariff or commission order it came from.
What electricity costs you now
A high rate makes every avoided kilowatt-hour worth more. This is why the north-east pays back faster than its sunshine suggests, and why a cheap-power state can be a poor investment under a bright sky.
What the system costs installed
Directly proportional: a price 60% higher is a payback roughly 60% longer, before incentives. See the cost calculator for the two published bases and why they differ.
How fast electricity prices rise
The slider above. It is the assumption most often hidden in other tools, and it is the one worth testing at both ends before you believe any payback figure, including this one.

What is subtracted along the way

A payback figure that counts only savings is not a payback figure. This model deducts routine maintenance every year and one inverter replacement in year twelve, both listed under the results with the values used. It does not deduct a roof replacement, an insurance increase, or the cost of removing and reinstalling panels if the roof is redone — and it does not add the resale value of the system, which research suggests is real but which we do not model because the evidence is not clean enough to compute from.

Payback by state

Solar payback in 2026 runs this same calculation across every state we publish on an identical house, so the comparison measures policy and price rather than a different reader in each state. The ranking is not the one most people expect.

Questions

What exactly is being paid back?
The net cost - the installed price less every credit you can actually claim. Each year the system saves you the bill you would otherwise have paid, less maintenance, and in year twelve the model subtracts an inverter replacement. Payback is the year the running total of those savings first exceeds the net cost. The chart above shows the crossing rather than asserting it.
Why does payback change so much when I move the escalation slider?
Because the saving is a bill you stop paying, and that bill grows. At 2.5% a year the electricity you avoid in year 20 costs 64% more than the same kilowatt-hours today. Assume a higher rise and payback shortens; assume prices flat and it lengthens considerably. No calculator knows the right value, which is why this one puts it under your hand instead of burying it.
Is payback the right way to judge a solar system?
It is the most legible measure, not the most complete one. It ignores everything after the crossing, so it treats a system that repays in year 11 and then earns for 14 more the same as one that repays in year 11 and fails in year 12. The 25-year net and the rate of return, both shown above, capture what payback throws away.
Why is payback so different between two sunny states?
Because sunshine is not what decides it. What a state pays for exported electricity, what electricity costs there to begin with, and what installation costs locally all move payback more than irradiance does. Arizona is the clearest case on this site: it is sunnier than most states we publish and pays back slower than several of them.

The other calculators

All of them run the same engine on the same data, so two can never disagree. They differ in what they put first.

A screening estimate from published data, not a quote and not tax or financial advice. Every input is listed under the results with the source it came from and the date it was read; the formulas are on the methodology page. Confirm against real quotes, and with a professional, before relying on any figure here.

Published 6 September 2026. Data last verified 6 September 2026. Rates: EIA 2026-07. Found a figure that looks wrong? Tell us — we publish corrections.