Construction Calculators

Rafter Length & Roof Pitch Calculator

Enter the run and a pitch (X:12, degrees or percent) to get common and hip/valley rafter length with overhang, plus the pitch in every unit. Pure geometry, imperial or metric.

Inputs

Results

Fill the form and press Calculate.

Common length = √(run² + rise²). Hip/valley assumes two equal-pitch planes meeting at a square corner: plan run = common run × √2. Geometry only; follow your local code and an engineer or span table for sizing.