Roof Pitch Calculator

How the Roof Pitch Calculator works

Formula. Pitch ratio = rise / run. Angle in degrees = arctangent(rise / run) × (180 / π). Percent grade = (rise / run) × 100. The “/12” display is round((rise / run) × 12).

Example. A rise of 6 over a run of 12 is 6/12. The angle is arctangent(0.5) × (180 / π) = 26.57 degrees, and the percent grade is 50%.

Limitation. The page reports the geometry of the two numbers entered. It does not look up a pitch factor for roof area.