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Free solar calculators
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Savings and paybackCost, yearly savings, payback and 25-year profit with every assumption editable.
System sizeKilowatts, panel count and roof area from your bill or usage.
Battery backup sizerCapacity, power and cost to keep essentials running in an outage.
Power station runtimeRuntime, right-size capacity and solar recharge time for any brand.
Plug-in solar savingsWhat a balcony or plug-in kit makes and saves in your state.
Which solar fits me?Four questions to the right kind of solar for your home.
Where our numbers come from
Electricity prices come from the US Energy Information Administration's monthly residential averages. Sunshine comes from NREL's PVWatts and National Solar Radiation Database. Installed prices use a $3.00 per watt midpoint between EnergySage's 2026 marketplace data and SEIA/Wood Mackenzie's 2026 market report. See our editorial policy for how we update them.
Want an estimate for your exact address, including roof angle? NREL's free PVWatts tool is the industry standard. Find it in our trusted resources.