Roof Pitch Calculator
Convert between rise/run, degrees, and x/12 roof pitch, and compute rafter length with overhang.
Processed locally in your browser — nothing is uploaded.
Inches of rise per 12 in of run
Usually half the building width — leave blank to skip
Results
- Pitch
- 6/12
- Angle
- 26.57°
- Slope
- 50%
- Pitch multiplier
- 1.118
Sloped length per foot of horizontal run
Rafter length is plumb-cut to plumb-cut along the slope; add for ridge boards and seat cuts.
About Roof Pitch Calculator
Start from whichever number you have — a measured rise and run, a pitch like 6/12, or an angle in degrees — and get all three plus the slope percentage and pitch multiplier. Add a horizontal run and overhang to get the rafter length via the Pythagorean theorem.
Common uses
- Translate a 26.6° measurement into a 6/12 pitch
- Cut rafters to length for a shed roof with a 1 ft overhang
- Find the pitch multiplier for shingle takeoffs
Example
Input
Pitch 6/12, run 12 ft, 1 ft overhang
Output
26.57° · 50% slope · multiplier 1.118 · rafter 14.53 ft
Limitations
- Rafter length is the plain slope diagonal — ridge-board thickness and birdsmouth cuts are extra