Roof Pitch Calculator
Calculate roof pitch from rise and run.
How It Works
Pitch (in 12) = Rise ÷ Run × 12. Angle = atan(Rise ÷ Run). Slope % = Rise ÷ Run × 100.
Example
For a 6 in rise over 12 in run: pitch = 6 in 12, angle ≈ 26.6°, slope = 50%.
Frequently Asked Questions
What does "4 in 12" mean?
It means the roof rises 4 inches for every 12 inches (1 foot) of horizontal run.
What is a low-slope roof?
Slopes under about 3 in 12 are considered low-slope and often require specialized roofing systems.
Why does pitch matter?
Pitch determines the roof surface area, the type of underlayment needed, and walking safety.