About this tool

Roof Pitch Calculator is a free tool for homeowners, contractors, and roofers. Enter rise and run, a degree angle, or a pitch ratio (X:12) to instantly calculate pitch ratio, angle in degrees, slope percentage, rafter multiplier, and rafter length. Includes a live SVG roof diagram and a reference chart of 20+ common roof pitches. All calculations run in your browser — no account needed, no ads, completely free.