Solar panel cost calculator
Turn a power bill into an installed price, a DIY price, yearly savings and a payback time. Every price below carries a source and a date.
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What goes into the price
Solar cost is size times price per watt. The size comes from your bill: how much you use, and how much sun your state gets. The price per watt is a market number, so it is the part that goes stale first. We show the source and date next to every figure, and you should check them against real quotes.
The formulas, with the constants
- installed cost = kWdc x 1,000 x $2.49 per watt
- DIY cost = kWdc x 1,000 x $1.00 to $1.50 per watt
- yearly savings = smaller of (production, usage) x electricity rate
- payback = installed cost / yearly savings
The $2.49 per watt figure is the national median installed price from EnergySage's H2 2025 marketplace data (as of 2026-11). The $1.00 to $1.50 per watt DIY range is a BillToSolar planning range for equipment kits (as of 2026-11), not a quote, so check current kit prices at the shops linked in your results. We apply no state multipliers because we have no sourced ones.
A worked example
The average Texas home uses 1,096 kWh a month and pays 14.9 cents per kWh (EIA, 2024 residential averages). That is 13,152 kWh a year. Sized to cover all of it, the tool returns 9.3 kWdc and 23 panels, an installed estimate of $23,046 and a DIY equipment range of $9,255 to $13,883. Yearly savings come to about $1,960, which is a payback of 11.8 years before any incentive.
Taxes and incentives
The 30% federal tax credit ended for homeowner purchases after December 31, 2025. The estimates here include no federal credit. Some states, utilities and local programs have their own incentives, and net metering rules change what a kilowatt-hour you export is worth. Look those up for your address before you rely on a payback figure.
Why payback is a range in real life
Electricity rates change, panels lose a little output each year, and your use will change if you add an electric vehicle or a heat pump. This calculator holds today's rate flat, so read the payback as a comparison between options, not a forecast. Cutting your use first shortens payback because you buy a smaller system.
Planning estimate. Permits, interconnection approval and a licensed electrician are required for grid-tied systems.
Questions
How much do solar panels cost per watt?
The national median installed price used here is $2.49 per watt (EnergySage, H2 2025, as of 2026-11). Quotes vary by state, installer, roof and equipment, so treat it as a midpoint and collect several real quotes.
Is there still a federal tax credit?
The 30% federal tax credit ended for homeowner purchases after December 31, 2025. Some states, utilities and local programs still offer incentives, and rules differ for businesses, so check your own situation.
How is payback calculated?
Payback is installed cost divided by yearly savings. Savings are the smaller of what the system makes and what you use, times your electricity rate. If your bill shows no usable rate, the state average is used.
Why is the DIY price so much lower?
The DIY range covers equipment kits only, at $1.00 to $1.50 per watt. It leaves out labor, permits, inspections, interconnection fees and your own time, and you still need a licensed electrician for any grid connection.
Does cost go up with battery storage?
Yes. The headline cost here is panels and inverter. Batteries add a separate cost, which the battery calculator on this site sizes. Prices move often, so check current listings.