Roof Pitch & Rafter Calculator
Pitch angle and rafter length from rise and run.
Pitch
16.7°
Rafter
1,044 mm
Slope factor
1.044
Worked example
A rise of 300 mm over a run of 1,000 mm is a pitch of about 16.7 degrees. The rafter along that triangle is about 1,044 mm, and the slope factor is 1.044.
FAQ
- What are rise and run?
- Rise is the vertical height. Run is the horizontal distance. Both are in millimetres here.
- What is the slope factor?
- Rafter length divided by run. Multiply a plan length by the factor to get the sloped length.
- Is pitch the same as a rise-per-run fraction?
- A 300:1000 rise is the fraction. The degrees are the angle of that triangle.