Formula and method
Pitch per 12 = 12 × rise/run. Angle = arctan(rise/run). Sloping length = √(rise² + run²).
Worked example
A rise of 3 over a horizontal run of 6 gives a 6-in-12 pitch, 50% slope and an angle of about 26.565°.
Roof Pitch Calculator
Convert rise and horizontal run to roof pitch, angle, slope percentage, sloping length and a plan-area multiplier.
Printed from Calxy · https://www.calxy.net/other/roof-pitch-calculator
Roof pitch per 12 units of run6.0000 in 12
same length unit
0 – 1000000000
same length unit
0.000001 – 1000000000
Roof pitch per 12 units of run
6.0000 in 12
- Roof angle26.5651 degrees
- Slope50.00%
- Sloping length6.7082 input length units
- Area multiplier from horizontal plan1.1180
Run is the horizontal distance, not the sloping rafter length or necessarily the full building span. No ridge, overhang or structural load allowance is included.
How this was calculated
Pitch per 12 = rise ÷ run × 12.
Angle = arctan(rise/run). Sloping length = √(rise² + run²).
Frequently asked questions
Is run the rafter length?
No. Run is horizontal distance. Rafter length follows the slope and is longer when the rise is positive.
Last updated . Results are estimates for informational purposes only.