Roof Pitch Calculator
Calculate roof angle and percent grade from vertical rise and horizontal run.
How to use
- Enter vertical rise.
- Enter a positive horizontal run in the same unit and calculate.
Capabilities and scope
The roof section is treated as a right triangle using atan(rise/run) and rise/run×100.
How it works
angle=atan(rise/run); grade%=rise/run×100.
Example
Rise 3 over run 12 gives about 14.04° and 25% grade.
Useful for
- Convert roof rise/run to degrees
- Compare pitch dimensions with percent slope
Before you use it
- Local pitch notation, minimum roof-slope codes, and actual rafter length require separate checks.
Frequently asked questions
How do I enter a 4:12 pitch?
Use rise=4 and run=12 in the same unit.