Free Roof Pitch Calculator
Calculate roof pitch as rise/run, angle in degrees, and pitch factor. Enter the rise and run to determine your roof slope.
Vertical rise per 12 inches of run
Typically 12 inches (standard pitch notation)
Pitch (X/12)
6.0
Pitch (X/12) vs Rise
How to Calculate Roof Pitch
Formula
Pitch = Rise / Run (typically expressed as X:12)
Angle = arctan(Rise / Run) in degrees
Pitch Factor = sqrt(1 + (Rise/Run)²)
Roof pitch is expressed as the number of inches of rise per 12 inches of horizontal run. For example, a 6/12 pitch rises 6 inches for every 12 inches of run. The pitch factor is used to convert footprint area to actual roof area.
Example Calculation
A roof with 6 inches of rise per 12 inches of run (6/12 pitch).
- 01Pitch = 6/12
- 02Angle = arctan(6/12) = arctan(0.5) = 26.6 degrees
- 03Pitch factor = sqrt(1 + 0.5²) = sqrt(1.25) = 1.1180
- 04Slope = 0.5 × 100 = 50%
Frequently Asked Questions
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