How many panels do you need? What will it cost — including inverter and battery? What's your payback period? Find out in 60 seconds.
Based on 2026 US solar costs, state electricity rates, and real peak sun hour data
To illustrate what our calculator produces, here are real worked examples for four common scenarios using 2026 EIA electricity rates and NREL peak sun hour data.
18 panels (7.74 kW) · 430W each · 315 sq ft roof space
Panels: $22,059 · Inverter: $2,129 · Labor: $3,309
Total installed: $27,497 · Annual savings: $1,470
Payback: 18.7 yrs · 25-yr net savings: $9,253
19 panels (8.17 kW) · 430W each · 333 sq ft roof space
Panels: $23,283 · Inverter: $2,180 · Labor: $3,492
Total installed: $28,955 · Annual savings: $3,360
Payback: 8.6 yrs · 25-yr net savings: $55,045
23 panels (9.89 kW) · 430W each · 403 sq ft roof space
Panels: $28,185 · Inverter: $2,387 · Labor: $4,228
Total installed: $34,800 · Annual savings: $2,640
Payback: 13.2 yrs · 25-yr net savings: $31,200
13 panels (5.59 kW) · 430W each · 228 sq ft roof space
Panels: $15,932 · Inverter: $1,871 · Labor: $2,390
Total installed: $20,193 · Annual savings: $1,848
Payback: 10.9 yrs · 25-yr net savings: $25,807
The number of solar panels you need depends on three things: how much electricity you use, how much sun your location gets, and how large the panels are. Our calculator handles all of this automatically.
We convert your monthly bill to kWh using your state's 2026 electricity rate. The US average is 903 kWh/month at 18.05¢/kWh ($163/month). Your state's rate may be higher or lower.
Arizona and Nevada get 6.5 peak sun hours per day — meaning panels produce far more power than in Washington (3.5 hrs). Fewer sun hours = more panels needed for the same output.
Most modern solar panels are rated at 430W. We divide your system size (in watts) by the panel wattage to get the minimum number of panels — always rounding up to the next full panel.
Every solar system needs an inverter to convert DC power from panels to AC power for your home. Grid-tied inverters cost $1,200–$2,500 for typical home systems. Batteries are optional — they store excess solar energy for nighttime use or outages, and cost $9,000–$18,000 per unit installed.
Not sure of your kWh usage? Start here to understand your current bill first.
Estimate Bill →Explore wind, biogas, and micro-hydro as complements or alternatives to solar.
Explore Alternatives →Detailed 2026 solar pricing for every US state — with tips on getting the best deal.
Read Guide →The table below shows typical 2026 solar installation costs and estimated annual savings for a 2,000 sq ft home using state-average electricity rates from the US Energy Information Administration (EIA) and peak sun hour data from NREL.
| State | Rate (¢/kWh) | Sun Hrs/Day | System Size | Panels | Installed Cost | Annual Savings | Payback |
|---|---|---|---|---|---|---|---|
| California | 28.0¢ | 5.5 | 8.1 kW | 19 | $23,085 | $3,024 | 7.6 yrs |
| Texas | 14.0¢ | 5.5 | 7.9 kW | 19 | $22,515 | $1,512 | 14.9 yrs |
| Florida | 14.0¢ | 5.5 | 7.9 kW | 19 | $22,515 | $1,512 | 14.9 yrs |
| New York | 22.0¢ | 4.0 | 10.8 kW | 26 | $30,780 | $2,376 | 12.9 yrs |
| Arizona | 15.4¢ | 6.5 | 6.5 kW | 16 | $18,525 | $1,663 | 11.1 yrs |
| Massachusetts | 31.5¢ | 4.0 | 10.8 kW | 26 | $30,780 | $3,402 | 9.0 yrs |
| Colorado | 15.0¢ | 5.5 | 8.0 kW | 19 | $22,800 | $1,620 | 14.1 yrs |
| Illinois | 15.0¢ | 4.0 | 11.0 kW | 26 | $31,350 | $1,620 | 19.4 yrs |
| Washington | 12.0¢ | 3.5 | 12.6 kW | 30 | $35,910 | $1,296 | 27.7 yrs |
| Georgia | 13.5¢ | 5.0 | 8.7 kW | 21 | $24,795 | $1,458 | 17.0 yrs |
Sources: EIA State Electricity Profiles (May 2026), NREL PVWatts peak sun hours, EnergySage 2026 cost benchmark ($2.85/W installed). Assumes 900 kWh/month baseline, 85% system efficiency. See full 50-state breakdown →