About RoofPitch

RoofPitch is a free, browser-based roof pitch calculator. Enter your rise and run and you instantly get the pitch (X:12), the roof angle in degrees, the slope percentage, the rafter length, and the roof area multiplier — the numbers roofers, framers, and DIY builders actually need.

Why we built it

Pitch is the single most important number on a roof — it controls material choice, cost, walkability, snow shedding, and rafter length. But most online calculators only give you the angle, or only the ratio, and few explain the multiplier that drives your material order. We wanted one clean tool that gives roofers and homeowners every derived number in one place, with a live diagram that makes the geometry obvious.

How it works

The math is plain trigonometry. The pitch ratio is (rise ÷ run) × 12. The angle is atan(rise ÷ run) × 180 ÷ π. The rafter length is the hypotenuse from the Pythagorean theorem: √(rise² + run²). The area multiplier is rafter ÷ run. Everything runs locally in your browser in a fraction of a millisecond, so you can tweak numbers and watch the diagram update live.

Privacy

No upload. No server. No storage. No account. Your inputs are never transmitted anywhere — the calculator is a static page and all computation happens in your browser. See our privacy policy.

Contact

Questions or feedback: [email protected]