Home › Electric bill and solar offset calculator
Calculator · Updated August 2026
Electric bill and solar offset calculator
Enter your bill and your state. It works backwards to system size and production value.
Ranked #1 by Solar Power World · Inc. 5000 · 20,000+ installations
The calculator
Start from your monthly bill
Sizing to cover 100% of usage is rarely the right answer where export credit is below the retail rate. Treat this as the upper bound, not the recommendation.
This is an estimate, not a savings guarantee.
It uses published utility rates, NREL regional sun data and a standard system derate. It does not know your roof orientation, your shading, your usage pattern or what your utility will charge next year. No solar company can honestly guarantee savings, and any that does is describing a model rather than making a promise.
What this actually calculates
It works backwards from your bill. Your bill divided by your rate gives kilowatt-hours. Kilowatt-hours divided by what a kilowatt of panels produces in your state gives a system size. That size multiplied back out gives annual production, and production multiplied by your rate gives the value of what the system makes.
Notice what it does not do: it does not tell you your savings. Production value and savings are different numbers, and the gap between them is where most solar marketing goes wrong.
Why production value is not savings
Some of your production is exported, and exports usually pay less
Power you use at the moment it is made offsets electricity at the full retail rate. Power you export is credited at whatever your state's export structure pays. In Pennsylvania and New Jersey that is the retail rate, one for one. In California under the Net Billing Tariff it is a fraction of retail. In Ohio it is the generation rate rather than the full rate. Same array, very different economics.
You keep paying to be connected
Customer charges, minimum bills and demand-related riders continue whether your roof produces or not. Nobody's bill goes to zero.
You still have to pay for the system
Whether that is a purchase price, a loan payment or a PPA rate, the cost side has to be subtracted. A system that produces $2,000 of electricity a year while costing $1,700 a year is worth $300, not $2,000.
How the numbers are built
Rates come from published utility tariffs in the 12 states where we carry verified figures, and from the EIA statewide residential average elsewhere — those pages say so explicitly. Production uses NREL regional annual average peak sun hours with a 80% system derate, which accounts for inverter losses, wiring, soiling and temperature. It assumes a well-oriented, largely unshaded roof.
What would change your real number most
Shading, first and by a distance. Then roof orientation — east and west planes lose meaningful production against south. Then usable roof area, which frequently caps the system below what your usage would justify. Then your usage pattern across the day, which decides how much you self-consume rather than export. None of those are knowable from a bill amount, which is why this is a starting point rather than a quote.
Doing this in the right order
If your usage is high because the house leaks heat, reducing usage is cheaper per kilowatt-hour avoided than generating it. Air sealing, attic insulation and a heat pump water heater shrink the system you need. Solar first and efficiency second means paying to generate power you did not have to use.
The residential federal tax credit (25D) ended for systems purchased after December 31, 2025.
You will still see ads promising a 30% credit that “ends December 31.” Read the date on them. If you buy a system today as a homeowner, you cannot claim that credit. What remains under 48E applies to the owner of the system — which, under a PPA, is us. SolarAmerica does not provide tax advice; talk to your tax professional about your situation.
Other calculators
Who you would be working with
SolarAmerica
We design your system and manage the project; installation is performed by vetted licensed partners in your area. SolarAmerica is not itself the installing contractor.
Questions
The things people actually ask
How do I estimate solar savings from my electric bill?
Divide your bill by your rate per kilowatt-hour to get usage, then divide annual usage by what a kilowatt of panels produces in your area. That gives system size. Multiply back out for production. Production value is not savings — you still subtract the cost of the system and account for exports being credited at less than retail in many states.
Will solar eliminate my electric bill?
No. You remain connected to the grid, you keep a customer charge, and you draw power at night. Solar offsets a portion of usage.
Is this calculator a quote?
No. It uses a statewide or utility-level rate and a modeled production figure. It knows nothing about your roof orientation, shading or usable area, all of which move the result materially.
What derate does it use?
80% of nameplate, which is a standard assumption covering inverter losses, wiring, soiling and temperature effects on a well-oriented, largely unshaded roof.
Get the number for your actual roof
About 60 seconds. No cost, no obligation, and we will tell you if solar does not make sense for your home.
Ranked #1 by Solar Power World · 20,000+ installations · Licensed installers