Roof Pitch Calculator
Translate a common rise-over-run roof measurement into geometry useful for roofing area and layout checks.
Roof pitch6:12
Angle26.57°
Slope50%
Pitch factor1.118
How this tool works
Angle = arctan(rise ÷ run). Slope percent = 100 × rise/run. Pitch factor = √(1 + (rise/run)²).
Example
A 6:12 roof is about 26.6° with a slope factor near 1.118.
Common questions
Is roof pitch always measured over 12 inches?
US roof pitch is commonly expressed as inches of rise per 12 inches of horizontal run, but the calculator accepts any consistent rise and run.
What is the slope factor for?
Multiply horizontal plan area or run by the factor to estimate corresponding sloped length/area for a simple plane.