Solar tools

Every tool is free, works without an account, and keeps your information in your browser.

Solar calculator

The full estimate for your address: production, savings, every way to pay, and a plain verdict.

Put any number of quotes side by side on true price, cost per kWh, fees, warranties and red flags.

Test system sizes, batteries, panels and financing for your home in one table.

Reveal the hidden markup in "low APR" solar loans and the true interest rate.

Cash, loan, lease and PPA side by side over 25 years.

Bill savings and backup value, counted separately.

Replace the roof first, or install now and pay to reinstall later?

Payments, interest, and savings versus payments over time.

Simple and discounted payback, ROI and annual return.

kW, panel count and roof area from your usage.

Savings from a community solar subscription.

Loan payoff, lease transfer or buyout at closing.

Compare actual production with what your system should make.

Fact-check what a salesperson told you.

Your cancellation deadline and a ready-to-send letter.

How much output your roof's direction and pitch cost you.

How fast prices have really risen in your state since 2010.