Every other "free solar calculator" online does the same thing: asks for your email or phone number, then sells you to installers. We got tired of it.
SolarCalc is different: no email, no phone, no sales calls. You enter your numbers, you get your estimate, you leave. That's it.
Every number you see comes from authoritative public sources:
For a standard south-facing roof with no significant shading, our estimates are within ±10% of professional installer quotes. This is an independent estimate, not a binding quote. Solar installation costs vary with roof complexity, local permit fees, and installer competition — always get 3+ quotes before deciding.
SolarCalc is free. We may earn a small commission if you choose to compare quotes through EnergySage (at no cost to you). We do not sell your data. We do not run ads that track you.
SolarCalc is open source (MIT license). You can view, modify, and run the entire codebase yourself. View on GitHub →
Questions, suggestions, or found a bug? Open an issue on GitHub.