Formula
Pitch12 = rise ÷ run × 12. Angle = arctangent(rise ÷ run). Slope factor = √(1 + (rise ÷ run)²).
Roof Pitch Calculator
Convert rise and run into pitch notation, equivalent angle, and slope factor.
How this roof pitch estimate works
Rise and run describe the same roof slope in different ways. This tool reports the familiar :12 pitch, the equivalent angle, and a slope factor for surface-area estimates.
Worked example
A 6 inch rise over a 12 inch run is a 6:12 pitch, about 26.565°, with a slope factor of approximately 1.118034.
Before you buy
Use the result to check a measurement or supply a slope factor to another calculator. Verify unusual or inaccessible roofs with a qualified professional.
Assumptions
Defaults are starting points. Replace coverage, density, package yield, spacing, and allowance values with the product or plan you are actually using.
Limitations
Pitch alone does not describe the whole roof. It cannot account for multiple planes, dormers, valleys, hips, or safe access conditions.