How it works
Pitch = rise ÷ run × 12 (inches of rise per 12 of run); angle = arctan(rise ÷ run); slope factor = √(rise² + run²) ÷ run.
Free calculator / Roofing
Roof pitch calculator.
Turn a rise and run into a roof pitch, its angle in degrees, and the slope factor that converts flat area to roof area.
Your numbers
Change any value. The result updates here in your browser.
Your answer
A quick example
A roof that rises 6 inches over 12 of run is a 6/12 pitch: about 26.57 degrees, with a slope factor of 1.118.
This is a calculation from numbers you supply, not financial or tax advice. Check assumptions before making a decision.