Roof Pitch Calculator

How to use this tool

1. Enter the vertical rise and the horizontal run in the same units.
2. Press Generate to see the pitch, slope and angle.
3. Use the pitch figure when comparing roofing materials, which often state a minimum pitch.

Worked example

With a rise of 6 and a run of 12, the pitch is 6 / 12 x 12 = 6:12, the slope is 6 / 12 x 100 = 50%, and the angle is arctan(0.5) = 26.57 degrees.

What this tool does not do / Limits

This is pure geometry from the two numbers you enter. It does not check structural strength, local building rules, snow or wind loads, or whether a material suits the pitch, so confirm those before building.

Frequently asked questions