Construction
Roof Pitch Calculator
Enter any of: rise/run, angle in degrees, or slope %. Get the other two — plus rafter length if you give a horizontal run.
Enter the rise (inches per 12 inches of run).
Common pitches
| Rise/Run | Angle | Use |
|---|---|---|
| 2/12 | 9.5° | Low-slope, special membrane needed |
| 4/12 | 18.4° | Min for asphalt shingles |
| 6/12 | 26.6° | Most common residential |
| 9/12 | 36.9° | Steep — extra labor |
| 12/12 | 45° | Very steep, dramatic |
FAQ
What does 6/12 mean? +
For every 12 inches of horizontal run, the roof rises 6 inches. So 6/12 is a moderate pitch.
What is the minimum pitch for shingles? +
4/12 is the manufacturer minimum for standard asphalt shingles. Below that, you need underlayment or a low-slope membrane.