Solar Calc

Solar Payback Calculator

Find your break-even year from net cost and yearly savings — with or without rising electricity rates — plus lifetime savings.

Payback is the year your accumulated electricity savings finally cover what the system cost you. Enter the net cost (after the 30% federal credit) and your first-year savings, then adjust the rate-increase assumption to see how much sooner rising utility prices bring break-even.

Your numbers

Results update as you type.

After the 30% federal credit.

US rates have historically risen 2–3%/yr.

Payback period

Simple payback (flat rates)
25-year savings
25-year return on cost

Simple vs. escalated payback

The "simple" figure assumes today's rate never changes — a deliberately conservative floor. The headline payback grows your yearly savings by the rate-increase you set, which is closer to how utility bills have actually behaved. The gap between the two is a fair sense of the uncertainty: your real payback usually lands between them, closer to the escalated number in markets where rates climb steadily.

Frequently Asked Questions

What is a good solar payback period?

Under 7 years is strong, 7–11 years is reasonable, and beyond 11 years the case weakens unless electricity prices rise. Because panels usually last 25+ years, even a 10-year payback leaves many years of essentially free electricity.

How does the rate-increase setting change payback?

Rising electricity prices make each year of savings larger than the last, so payback arrives sooner than the flat-rate "simple" figure. US residential rates have historically risen around 2–3% per year, though the future is not guaranteed.

Why enter the net cost instead of the sticker price?

Payback should be measured against what you actually pay. Net cost is the system price after the 30% federal tax credit (and any other upfront incentives), which is the number your savings have to recover.

Does this include financing interest?

No — this is a cash-payback model. If you finance the system, use the Solar Loan Calculator to see the monthly payment and interest, then compare that against your bill savings.

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