Roof pitch calculator

6/12 factor: 1.118. Angle: 26.6 degrees.

Job sheet

Plumb roof pitch job sheet

6 in 12.

  • Pitch factor1.118Slope length of a 12 inch run, divided by 12.
  • Angle26.6 degrees
  • Slope length13.42 ftFor a 12 ft horizontal run.
Plumb roof pitch job sheet
6 in 12.

Pitch factor: 1.118 (Slope length of a 12 inch run, divided by 12.)
Angle: 26.6 degrees
Slope length: 13.42 ft (For a 12 ft horizontal run.)

Pitch factor

Factor = square root of (12² + rise²), divided by 12. A 4/12 is 1.054. A 12/12 is 1.414. The factor is not a shingle count. Squares and bundles are on roofing. Rafter length to the plate, without the tail, is on rafters.

FAQ

What is the pitch factor for a 6/12 roof?

A 6 inch rise in 12 inches of run is a factor of 1.118. Multiply the flat area by that factor to get roof surface. A 12 foot run becomes 13.42 feet of slope.

How many degrees is a 6/12 pitch?

26.6 degrees. The angle is the arctangent of rise over 12. A 12/12 pitch is 45 degrees. A 4/12 is lower, about 18.4 degrees.

Sources

  1. NIST Handbook 44: The foot is the unit. The factor is geometry: hypotenuse of a 12 inch run and the rise, divided by 12.