Solar Panel Cost Per Watt Calculator

Is your solar quote fair? Enter your total cost and system size — see your gross and net $/W versus the 2026 market average.

Your solar system

Total system cost?

System size?

Incentives & tax credits?

Gross cost per watt

$2.80 / W

System size10.0 kW (10,000 W)

Net cost per watt$1.96 / W

Net system cost$19,600

vs. market avg ($3.00/W gross)−$0.20 / W

Price ratingGood

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How to Use This Calculator

Enter your total system cost

The total system cost is the all-in price before any tax credits or rebates — panels, inverter, mounting hardware, wiring, installation labor, permits, and interconnection fees. This is the number on your installer's final contract. US residential solar averages $2.50–$3.50/W gross in 2026, putting a 10 kW system at $25,000–$35,000.

Enter your system size

Your system size in kW is on your installer quote. A 10 kW system has 10,000 watts of total panel capacity. The calculator divides total cost by total watts to get cost per watt.

Add incentives for net $/W

Enter your total incentives — primarily the 30% federal Investment Tax Credit (ITC). On a $28,000 system, the ITC is $8,400, making the net cost $19,600. Net $/W is what you actually pay after all credits and rebates. This is the most useful number for comparing solar quotes — it's what competitors charge net of all incentives they advertise.

The Formula

Gross Cost per Watt = Total System Cost ($) ÷ System Size (W) Net Cost = Total System Cost − Total Incentives Net Cost per Watt = Net Cost ($) ÷ System Size (W) System Size in Watts = System Size in kW × 1,000

Example: $28,000 total cost for a 10 kW (10,000 W) system = $2.80/W gross. After the 30% federal ITC ($8,400), net cost is $19,600 = $1.96/W net.

US Solar Price Benchmarks (2026)

How does your quote compare to the market?

Under $2.50/W gross: Excellent — significantly below market. Verify the quote includes all components and a reputable installer.
$2.50–$3.00/W gross: Good — below or at market average. Well-priced installation.
$3.00–$3.50/W gross: Average — standard market pricing. Normal for most installers.
$3.50–$4.50/W gross: Above average — may be justifiable for premium components or difficult installations (steep roof, complex wiring). Get comparison quotes.
Over $4.50/W gross: High — always get at least two more quotes. Some installers significantly overcharge, especially in markets with limited competition.

Note: Prices vary significantly by state. California, New York, and New England tend to run $3.00-$4.00/W. Texas, Arizona, and competitive Midwest markets often achieve $2.50-$3.00/W. Hawaii can exceed $4.00/W due to logistics and permitting costs.

FAQ

What is a good cost per watt for solar in 2026? ▼

A good gross cost per watt in 2026 is $2.50–$3.00/W for most US markets. The national average is approximately $2.80–$3.10/W gross. After the 30% federal ITC, net cost per watt typically falls to $1.75–$2.20/W. If you're quoted over $3.50/W gross, always get comparison quotes — the solar market is competitive and overpaying by even $0.50/W on a 10 kW system means $5,000 extra.

Why do larger solar systems cost less per watt? ▼

Larger systems have lower cost per watt because fixed costs (permits, site assessment, labor for electrical work, interconnection) are spread over more watts. A 5 kW and 15 kW system might have similar fixed costs of $5,000-8,000; the variable cost is only the panels and additional labor. This is why the per-watt cost drops as system size increases. It's also why adding panels to an existing system is usually cheaper per watt than the original installation.

Should I compare quotes on gross or net $/W? ▼

Always compare on gross $/W first — before any tax credits. Every quote should be reduced by the same 30% federal ITC (assuming you have sufficient tax liability), so comparing gross prices puts all quotes on equal footing. Some installers advertise "net after incentives" prices that may assume incentives you don't qualify for. If comparing quotes with different system sizes, use $/W rather than total cost — a $35,000 quote for 12 kW is better than a $30,000 quote for 9 kW.