Free — no sign-upSolar panel
Solar panel
savings calculator
Enter your monthly electricity bill and state to estimate system size, cost, annual savings and payback period.
Reflects 2026 rules50-state data25-year projection
2026 update: the 30% federal residential solar tax credit ended for costs paid after December 31, 2025. This calculator reflects that — see what changed.
How the estimate works
- Annual usage (kWh) = monthly bill ÷ state electricity rate × 12.
- System size (kW) = annual usage ÷ (sun hours × 365 × 0.8 system-loss factor).
- Gross cost = system size × state installed $/W.
- Net cost = gross cost (No federal residential solar tax credit is applied — the 30% credit (IRC §25D) was repealed for costs paid after December 31, 2025.)
- Annual savings = offset production × electricity rate; payback = net cost ÷ annual savings.
- 25-year savings compound electricity prices at ~3%/year.
The per-state figures (electricity rate, sun hours, installed $/W) are from EIA, NREL and EnergySage data for 2026 — see the data notes. They are state averages: your own utility rate and a real installer quote can differ by a good margin, and electricity prices move month to month. Confirm your utility's rate, local installed prices, and net-metering rules before relying on a payback number.
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Frequently asked questions
How accurate is this estimate?
It is a planning estimate based on your bill, typical state figures for electricity price, sun hours and installed cost, and standard system-loss assumptions. Real quotes vary with your roof, utility, and equipment. Always get quotes from licensed installers.
How is the system size chosen?
It is sized so that a south-facing, unshaded array would produce roughly your current annual electricity use. Orientation and shading then reduce the modelled production.
Is there still a 30% federal solar tax credit?
Not for a system you pay for in 2026 or later. The 30% federal residential solar credit (IRC §25D) was repealed by the One Big Beautiful Bill Act (signed July 2025) for expenditures made after December 31, 2025. Systems installed in 2025 or earlier that already qualified can still use the credit; new 2026+ owned installs get none. A solar lease or power-purchase agreement can still capture credit value indirectly, because the installer — not you — owns the system and can claim the separate commercial credit.
What about state and local incentives?
Those are not included here and can meaningfully improve the payback. Check your state energy office and utility for rebates, performance payments, and net-metering rules — with the federal credit gone, state and utility incentives now matter more than ever.
What is net metering and why does it matter?
It is the policy that decides what your exported solar power is worth. Full retail net metering credits every exported kWh at the price you pay to buy one — the best case. Newer schemes (avoided-cost export rates, time-of-use) pay far less for exports, which lengthens payback and makes batteries more attractive. Check your utility's current rules before buying.
How long do solar panels last?
Panels are typically warrantied for 25 years and keep producing beyond that at gradually reduced output (about 0.5% less per year). Budget for one string-inverter replacement around year 12–15; microinverters usually last the system's life.
Should I lease or buy?
Buying (cash or a low-rate loan) keeps all the long-term savings and, historically, the tax credit. A lease or power-purchase agreement has no upfront cost and, in 2026, is the one route where federal credit value can still reach a homeowner indirectly — because the installer owns the system and claims the separate commercial credit — but your savings are smaller. This calculator models an owned system.