Roof pitch calculator
Convert rise and run to pitch, pitch to degrees, and get the multiplier that turns a footprint into roof area.
Roof pitch chart
| Pitch | Angle | Multiplier | Walkable? |
|---|---|---|---|
| 1/12 | 4.8° | 1.003 | Low slope |
| 2/12 | 9.5° | 1.014 | Low slope |
| 3/12 | 14.0° | 1.031 | Yes |
| 4/12 | 18.4° | 1.054 | Yes |
| 5/12 | 22.6° | 1.083 | Yes |
| 6/12 | 26.6° | 1.118 | Yes |
| 7/12 | 30.3° | 1.158 | With care |
| 8/12 | 33.7° | 1.202 | With care |
| 9/12 | 36.9° | 1.250 | No — steep |
| 10/12 | 39.8° | 1.302 | No — steep |
| 11/12 | 42.5° | 1.357 | No — steep |
| 12/12 | 45.0° | 1.414 | No — steep |
| 14/12 | 49.4° | 1.537 | No — steep |
| 16/12 | 53.1° | 1.667 | No — steep |
| 18/12 | 56.3° | 1.803 | No — steep |
The multiplier (also called the slope factor) is √(1 + (rise ÷ 12)²). Multiply a roof’s flat footprint by it to get the actual sloped surface. Learn more in roof pitch explained.