Roof Pitch Calculator

Convert roof pitch formats and estimate rafter length from run and rise.

Same units as rise/run for rafter length

How to use

Pitch is often written as rise:run over 12 (e.g. 6/12). Percent slope = rise/run × 100.

Frequently asked questions

Do you store the numbers I enter?

Calculations run in your browser. Inputs are not sent to our servers.

Are the results guaranteed accurate?

Standard formulas are used. Double-check important decisions with a professional or official source.