Construction

Roof Pitch Calculator

Convert roof rise and run into pitch, angle and slope factor.

Rise

Run

Calculated Output

Pitch (rise in 12) (/12) 6

Angle (°) 26.565

Slope factor (×) 1.118

Formula: angle = atan(rise ÷ run); slope factor = √(rise² + run²) ÷ run

Step-by-Step Breakdown

1. Values used:

2. Rise = 6

3. Run = 12

5. Pitch (rise in 12) = 6/12

6. Angle = 26.565°

7. Slope factor = 1.118×

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The math behind it

Pitch is the rise over a 12 in run, e.g. '6/12'. Angle = arctan(rise ÷ run).

Slope factor = √(rise² + run²) ÷ run — multiply a roof's flat footprint area by this to get the sloped surface area.

Rise 6 in over run 12 in → pitch 6/12, angle 26.57°, slope factor 1.118.

What is a 'good' roof pitch?

4/12 to 9/12 is common for shingled roofs; below 2/12 needs special low-slope materials.