Solar quotes are hard to sanity-check because installers quote a single bottom-line number while the real drivers — your usage, your state's per-watt pricing, your sun exposure — stay hidden. This calculator works the other way: it builds the estimate from those drivers in the open, using the same 2026 state pricing data behind our 50-state comparison table. It runs entirely in your browser; nothing you enter is collected, and no installer will call you.
One 2026 reality check before you start: the 30% federal Residential Clean Energy Credit (Section 25D) expired on December 31, 2025. Customer-owned systems installed in 2026 get no federal credit, so this tool shows honest gross costs — unlike many older calculators still quietly subtracting 30%. Solar leases and PPAs can still capture value through the separate commercial credit (Section 48E), and state incentives still apply where they exist.
2026 Solar Cost & Savings Calculator
Solar Cost & Savings Estimator
2026 state averages — your real quotes will vary with roof, shading, and installer.
Estimates only — not a quote. Figures are gross 2026 costs: the 30% federal credit (Section 25D) expired after 2025, and state/utility incentives are excluded because they vary by program and budget cycle. Assumes a 25-year system life and ~2.5%/yr utility-rate inflation. Always compare at least three local quotes.
How the calculator works — every formula, in the open
Most online solar calculators are black boxes designed to capture your email. This one shows its work. Four steps turn your bill into an estimate:
| Step | Formula | Example (US avg: $165/mo bill) |
|---|---|---|
| 1. Annual usage | (bill × 12) ÷ state utility rate | $1,980 ÷ $0.165/kWh = 12,000 kWh/yr |
| 2. System size | (usage × offset target) ÷ (peak sun hours × 365) | 10,800 kWh ÷ (4.5 × 365) = 6.6 kW |
| 3. Installed cost | system watts × state $/watt | 6,600 W × $2.85 = $18,810 |
| 4. Simple payback | installed cost ÷ first-year savings | $18,810 ÷ $1,782 ≈ 10.6 years |
The inputs behind each state — average installed cost per watt, average residential utility rate, and average peak sun hours per day — are 2026 figures from aggregated installer pricing and utility data, the same set used across our state cost guides. Panel count assumes standard 400 W residential panels.
Worked examples: three real-world scenarios
Here's how the same monthly bill produces very different answers depending on where you live — which is exactly why a national average number is nearly useless for planning:
| Scenario | System needed | 2026 installed cost | Annual savings | Simple payback |
|---|---|---|---|---|
| Phoenix, AZ — $150/mo bill, 90% offset | ~4.9 kW (13 panels) | ~$11,800 | ~$1,620 | ~7 yrs |
| Los Angeles, CA — $250/mo bill, 90% offset | ~4.4 kW (11 panels) | ~$13,200 | ~$2,700 | ~5 yrs |
| Seattle, WA — $150/mo bill, 90% offset | ~10.6 kW (27 panels) | ~$28,400 | ~$1,620 | ~17.5 yrs |
Note the pattern: high electric rates and strong sun (California, Arizona) make solar pay back fast even at 2026 gross prices; cheap hydro power and weak winter sun (Washington) stretch payback past 15 years even though the hardware costs the same. Your state's rate and sun matter more than the sticker price.
What the estimate includes — and what it can't
Included: equipment (panels, inverter, racking, wiring), installation labor, permitting, and inspection — the standard scope of a turnkey installer quote, priced at your state's 2026 average per watt.
Not included: state and utility incentives (they can cut thousands off in NY, MA, NJ, IL — check your state's guide), a home battery (typically +$9,000–$15,000 installed), roof repairs or replacement before install, main-panel upgrades on older homes (+$1,500–$3,000), and premium equipment tiers. Real quotes typically land within ±15% of the state average — if a quote is more than ~20% above, ask the installer to itemize what's driving it before walking away; sometimes there's a legitimate reason (complex roof, premium panels), and sometimes there isn't.
How to use your result to vet installer quotes
The single most useful number the calculator gives you is your state's cost per watt. When quotes arrive, divide each bottom line by the system size in watts and compare: in 2026, a fair installed price falls between $2.40 and $3.30 per watt in most states. Also check the proposed system size against the calculator's recommendation — if you need ~7 kW and a salesperson proposes 12 kW, make them justify every extra panel with your actual usage data. Homeowners who compare three or more quotes save an average of $2,000–$5,000; our state-by-state comparison shows what's normal in your market.
You can't buy a rooftop install on Amazon — but you can measure your usage before sizing a system, and verify production after it's installed.
As an Amazon Associate we earn from qualifying purchases. Prices are approximate and set by Amazon.
Calculator FAQ
How does this solar panel cost calculator work?
It converts your monthly bill into annual kilowatt-hours using your state's average utility rate, sizes a system to your chosen offset target using your state's peak sun hours, then prices that system at your state's 2026 average installed cost per watt. Payback is installed cost divided by first-year savings. Every formula is published in the table above so you can check the math.
How accurate is the estimate?
Treat it as a benchmark, not a quote. It uses 2026 state-average pricing, rates, and sun data; real quotes typically land within about ±15% of the state average. Roof complexity, shading, equipment tier, and installer competition all move the number. Its main job is telling you whether the quotes you receive are in a reasonable range.
Does the calculator include the 30% federal tax credit?
No — because that credit no longer exists for 2026 home buyers. The 30% Residential Clean Energy Credit (Section 25D) expired December 31, 2025, so customer-owned systems installed in 2026 receive $0 federal credit and the calculator shows full gross cost. Leases and PPAs may still benefit indirectly via the separate commercial credit (Section 48E) claimed by the system's owner.
Does the estimate include state and utility incentives?
No — results are gross costs, because state programs vary too much by location and budget cycle to estimate reliably. In states with strong programs (New York's 25% state credit, Massachusetts SMART, New Jersey's SREC-II), your real net cost can be meaningfully better than shown. Check your state's guide on this site for current local incentives.
What size solar system do I need?
Most US homes need 6–10 kW to offset all their usage. Quick rule: annual kWh ÷ (peak sun hours × 365). A home using 10,800 kWh/yr in a 4.5-sun-hour state needs ~6.6 kW — about 17 panels at 400 W. The calculator does this for you, and the 70%/90% offset options show what a smaller, cheaper system would look like.
Is this calculator free, and do you sell my information?
Yes, and no. It runs entirely in your browser — no signup, no email capture, and nothing you type is sent anywhere or shared with installers. We're not a lead-generation site; we publish pricing data so you can negotiate from an informed position.
Related solar guides
Solar Panel Cost by State
Compare 2026 prices, incentives, and payback across all 50 states.
State Cost Comparison
Side-by-side per-watt pricing and payback periods nationwide.
Cost by System Size
6kW vs 8kW vs 10kW — prices, panel counts, and output by region.
Solar Cost FAQ
12 straight 2026 answers on pricing, payback, and the expired credit.
Solar Cost in California
A high-rate, high-sun market reshaped by NEM 3.0 net billing.
Commercial Solar Cost
Pricing, ROI, and the surviving 48E credit for businesses.