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Solar Panel Savings Calculator
Enter your electric bill and location details to estimate system size, upfront cost, payback period, and 25-year savings. Add any incentives you qualify for.
Your electricity use Free
System & incentive assumptions
The 30% federal homeowner solar credit ended for systems installed after December 31, 2025, so this starts at 0%. Enter a percentage only if you have a system placed in service by then, a carried-forward credit, or another incentive (state, local, or utility) you want to include.
Estimated Payback Period
0 years
25-year net savings: $0
0 kW
System size needed
$0
Cost before credit
$0
Cost after incentives
Savings over time
Year
Est. annual utility savings
Cumulative savings
Net position
"Net position" is cumulative savings minus your system cost after any incentives — once it turns positive, the system has paid for itself.
Quick answers
How accurate is this estimate?
This is a simplified planning estimate, not a quote. Real numbers depend on your roof's orientation and shading, local permitting costs, your specific utility's net metering policy (whether they credit you fully for excess power sent back to the grid), equipment choice, and installer pricing in your area. Get 2–3 real quotes before deciding.
What is the federal solar tax credit?
The Residential Clean Energy Credit let homeowners claim 30% of their solar system cost on their federal taxes. Under the One Big Beautiful Bill Act, that credit ended for systems installed after December 31, 2025, so buying solar with cash or a loan now carries no federal credit. Exceptions include systems placed in service by the end of 2025 (any unused credit can carry forward) and solar leases or power purchase agreements, where the installer owns the system and may claim business tax credits instead. State, local, and utility incentives may still exist, so check your area. This calculator starts at 0% and lets you enter any incentive you qualify for.
What if I don't own my roof, or I'm renting?
This calculator assumes you own your home and plan to stay long enough to benefit from the payback period. If you rent, or might move soon, a solar lease or power purchase agreement (PPA) works differently — usually lower savings but no upfront cost. Community solar (subscribing to a shared solar farm) is another option if rooftop solar isn't feasible for you.
How to use this calculator
It sizes a system from your electricity bill and a sun-hour figure, then compares the cost against a year of savings. The result is a rough payback, not a proposal.
Enter your average monthly electric bill and your price per kilowatt-hour. Both are on the bill, and using a seasonal average matters more than using last month's.
Pick peak sun hours for your region. The number is a daily average over the year, so a northern winter is already baked into it.
Enter the installed cost per watt from a real quote, not a national average. Quotes vary by roof, market, and equipment.
Set the incentive percentage only for a credit you actually qualify for and still exists.
Enter the utility rate increase you expect, then read the payback year and the 25-year cumulative row.
A worked example: a $180 monthly bill
At $0.16 per kWh, $180 is 1,125 kWh a month, or about 37.5 kWh a day. Divide by 4.5 peak sun hours and by the page's 0.8 allowance for real-world losses, and the system size is about 10.4 kW.
At $2.80 a watt installed, that is roughly $29,200 before any incentive. Against a yearly bill of $2,160, the simple payback is about 13.5 years.
Now change only the incentive box. At 30%, net cost falls to about $20,400 and payback drops to roughly 9.5 years. The system did not change; only the money did. That is why the percentage needs a source rather than an assumption, and why the box starts at zero.
For context on the incentive itself: the federal residential clean energy credit no longer applies to homeowner-owned systems placed in service after December 31, 2025. A state or utility rebate you can document still belongs in the field. An installer's estimate that assumes a federal credit you cannot claim is an estimate with a hole in it.
What your results mean
The payback is net cost divided by year-one savings. It is a simple, conservative measure that ignores financing costs, equipment degradation, inverter replacement, and the time value of money. A real financial model would push the break-even later, not earlier.
Year-one savings are assumed to equal your entire current bill, which quietly assumes the array covers all of your usage, exports nothing of value, and that nothing about your consumption changes. If you buy an electric car or add a heat pump, the bill changes and so does the calculation.
The 25-year cumulative row adds savings minus net cost. It uses your rate-increase assumption as a straight line, and utility rates do not move in straight lines.
Before treating any payback as real, get a production estimate for the actual roof: its pitch, its azimuth, and the shade on it. A national sun-hour figure cannot see the tree on the south side, and no amount of correct arithmetic fixes an input that was wrong.
Frequently asked questions
Why does the incentive box start at zero?
Because a credit you cannot claim should not improve the payback. Enter a percentage only for an incentive you have confirmed you qualify for, and check whether it is a credit, a rebate, or a performance payment.
Is the federal credit still available?
For homeowner-owned systems placed in service after December 31, 2025, the residential clean energy credit does not apply. State and utility programs vary. Check the IRS page and your state energy office rather than an installer's summary.
What are peak sun hours?
A way of expressing daily solar energy as the number of hours at full strength the sun would need to deliver it. Four to five is typical for much of the continental United States; the southwest runs higher and the northeast lower.
Does the calculator account for net metering?
Only implicitly. It assumes year-one savings equal your bill. A favorable net-metering rule can help, and a poor one that buys exports at a low rate will reduce the real savings.
What about a lease or a power purchase agreement?
Then you do not own the system and the federal tax credit is not yours. A lease payment is a different calculation, and the incentive field should stay at zero.
How long do the panels last?
Modules commonly carry production warranties of 25 years, and inverters often need replacing sooner. This page's 25-year window is a planning horizon, not a lifespan guarantee.
Sources & references
Sun hours and production losses are simplified here. These are the sources to check before signing anything.