Solar Panel Calculator: Savings & Payback
Would solar actually pay off for you? Enter your usage, local sun hours, and an installed price, and see your estimated annual savings, payback period, and 25-year return — instantly.
Or estimate: monthly bill ÷ rate.
Leave blank to auto-size to your usage.
Share of your usage solar can realistically cover.
Estimated annual savings
$0
with a 0 kW system
Estimates only — not financial advice. Actual savings depend on your roof, shading, tariff, and net-metering rules. Get a professional assessment before buying.
The next step: get real quotes
The numbers above are estimates. The only way to know exactly what solar costs on your roof is a real quote — and comparing three from local installers is the single best way to avoid overpaying. Look for installers certified in your region, ask each for the system size, total price, and estimated annual production, then check their production figure against the solar output estimator.
How this solar savings calculator works
It estimates production with the industry-standard formula: annual kWh = system kW × peak sun hours × 365 × 0.78, where 0.78 is a typical performance ratio covering inverter losses, temperature, wiring, and soiling. Savings are the offset kWh (capped at your usage × offset %) multiplied by your rate. Payback is net cost after incentives divided by annual savings, and the 25-year figure is simple savings × 25 minus net cost — conservative, since it ignores electricity price inflation.
If you leave system size blank, the calculator sizes a system to cover your annual usage, the same approach as our solar panel size calculator.
Solar savings FAQ
How much can solar panels save me per year?
Annual savings equal the solar electricity you actually offset multiplied by your price per kWh. A typical 6 kW system in a region with 4.5 peak sun hours produces roughly 7,700 kWh a year; at $0.15/kWh that's around $1,100–1,200 per year, capped by how much of your usage the system can cover.
How is solar payback period calculated?
Payback = net system cost (after rebates and tax credits) divided by annual savings. If a system costs $14,000, incentives cover 30% ($4,200), and it saves $1,400 a year, payback is $9,800 ÷ $1,400 = 7 years. Typical residential paybacks run 6–12 years.
What are peak sun hours?
Peak sun hours measure daily solar energy as equivalent hours of full-strength sun (1,000 W/m²). Cloudy northern regions get 3–3.5; temperate areas 4–4.5; sunny and desert regions 5–6.5. Your region's figure drives how much a given system produces.
Why doesn't solar cover 100% of my bill?
Production peaks at midday while usage often peaks mornings and evenings, and export credits are usually worth less than retail rates. Fixed standing charges also remain. That's why the calculator defaults to a 90% offset — adjust it to your utility's net-metering rules.
Is this solar calculator accurate?
It uses the standard estimate — production = system kW × peak sun hours × 365 × 0.78 performance ratio — which is a solid planning figure. A local installer's shade and roof analysis gives the final number; results here are estimates, not financial advice.