Solar savings & payback calculator (2026)
Free solar payback calculator using real state electricity rates, sun data, and the actual 2026 tax rules — no phantom 30% credit, no email.
Estimate your solar payback
Three inputs. Real local rates. An honest 2026 estimate.
Fine-tune (orientation, offset, financing)
Enter your bill to see your estimate.
- System size
- —
- Est. net cost
- —
- Annual savings
- —
- 25-yr savings
- —
Loan payment: —
Your state’s rules & the 2026 credit
Net metering: Select your state.
Incentives: Select your state.
The 30% federal residential solar tax credit (IRC §25D) expired on December 31, 2025. Homeowners who buy a system in 2026 do not receive a federal tax credit. Leasing or a PPA (third-party ownership) may still pass through some federal benefit via the commercial credit — always verify current federal and state incentives before signing.
Estimated annual production: —; gross cost —; panel count —.
Estimates only — not financial advice, and no federal credit applies to 2026 purchases. Your real numbers depend on roof, usage, utility, equipment, and quotes — verify and get itemized bids.
How this calculator works
We turn your monthly electric bill into annual kilowatt-hours using your state’s real electricity rate, then size a system to cover your chosen share of that usage given local sun hours. From there we estimate cost, subtract any incentives you actually qualify for in 2026, and compare the result to your annual bill savings.
The chain is intentionally simple and transparent:
- Annual usage = (monthly bill × 12) ÷ your state’s $/kWh rate.
- System size = usage ÷ (sun hours × 365 × performance ratio), adjusted for roof orientation.
- Gross cost = system watts × your state’s $/W.
- Net cost = gross cost − federal credit (0% in 2026) − state incentives.
- Payback = net cost ÷ annual savings. 25-year savings grows savings with rate inflation and trims them for panel degradation.
The assumptions we use
Every number below lives in a single config file, so updates apply everywhere on the site at once:
| Installed cost | $2.85/watt (national default; per-state overrides) |
|---|---|
| System performance ratio | 80% (inverter, heat, soiling, wiring losses) |
| Bill offset | 90% default (you still pay fixed grid charges) |
| Utility rate escalation | 3.5%/year |
| Federal tax credit | 0% for 2026 purchases (IRC §25D expired 2025-12-31) |
| Modeled lifetime | 25 years (with panel degradation) |
Why our number may be lower than other calculators
Many calculators still subtract a 30% federal tax credit. For systems installed in 2026 that credit is gone — the One Big Beautiful Bill Act ended the residential credit (IRC §25D) on December 31, 2025. Quietly keeping it in the math makes solar look thousands of dollars cheaper than it is. We’d rather show you the honest figure and let your state’s incentives and electricity prices do the talking.
Frequently asked questions
Is the solar calculator free and private?
Yes. It runs entirely in your browser, requires no email or sign-up, and makes no external calls — your numbers never leave your device.
Does it include the 30% federal tax credit?
No, because for 2026 purchases that credit no longer exists. The residential federal solar tax credit (IRC §25D) expired December 31, 2025. We model owned systems with a 0% federal credit so your payback reflects reality. Leases/PPAs may still pass through some benefit via the commercial credit.
How accurate is the payback estimate?
It’s a good directional estimate built from EIA rate data, NREL sun hours, and 2026 market install costs. Your real numbers depend on your roof, shading, exact usage, utility tariff, equipment, and the quotes you get — always compare itemized bids.
Can I see the formula?
Yes — the full model is described on this page, and every constant lives in one config file. We deliberately keep the math transparent rather than hiding it behind a lead form.
Run the numbers for your state
Open a state to see local rates, incentives, and the honest verdict.