Roof Pitch Chart
Convert between roof pitch, angle in degrees, slope factor, and grade percentage. The slope factor multiplies the flat (plan-view) area to get the actual sloped roof area.
| Pitch | Angle | Slope Factor | Grade % | Diagonal per ft |
|---|---|---|---|---|
| 1/12 | 4.8° | 1.0035 | 8.3% | 12.042" |
| 1.5/12 | 7.1° | 1.0078 | 12.5% | 12.093" |
| 2/12 | 9.5° | 1.0138 | 16.7% | 12.166" |
| 2.5/12 | 11.8° | 1.0215 | 20.8% | 12.258" |
| 3/12 | 14.0° | 1.0308 | 25.0% | 12.369" |
| 3.5/12 | 16.3° | 1.0417 | 29.2% | 12.500" |
| 4/12 | 18.4° | 1.0541 | 33.3% | 12.649" |
| 4.5/12 | 20.6° | 1.0680 | 37.5% | 12.816" |
| 5/12 | 22.6° | 1.0833 | 41.7% | 13.000" |
| 5.5/12 | 24.6° | 1.1000 | 45.8% | 13.200" |
| 6/12 | 26.6° | 1.1180 | 50.0% | 13.416" |
| 7/12 | 30.3° | 1.1577 | 58.3% | 13.892" |
| 8/12 | 33.7° | 1.2019 | 66.7% | 14.422" |
| 9/12 | 36.9° | 1.2500 | 75.0% | 15.000" |
| 10/12 | 39.8° | 1.3017 | 83.3% | 15.620" |
| 11/12 | 42.5° | 1.3566 | 91.7% | 16.279" |
| 12/12 | 45.0° | 1.4142 | 100.0% | 16.971" |
| 14/12 | 49.4° | 1.5366 | 116.7% | 18.439" |
| 16/12 | 53.1° | 1.6667 | 133.3% | 20.000" |
| 18/12 | 56.3° | 1.8028 | 150.0% | 21.633" |
| 24/12 | 63.4° | 2.2361 | 200.0% | 26.833" |
Highlighted rows are the most common residential pitches.
Understanding Roof Pitch
Roof pitch is expressed as rise over run, where the run is always 12 inches. A 6/12 pitchmeans the roof rises 6 inches for every 12 inches of horizontal run — equivalent to a 26.6° angle.
Common Roof Pitches
- 2/12 to 3/12 — Low slope. Requires special roofing (membrane, metal with sealant). Not suitable for asphalt shingles.
- 4/12 — Minimum pitch for standard asphalt shingles per most manufacturers.
- 5/12 to 6/12 — Most common residential pitch. Good water shedding, walkable for maintenance.
- 8/12 — Steeper. Better for snow shedding. Starting to get difficult to walk on.
- 10/12 to 12/12 — Steep. Dramatic appearance, excellent snow shedding, requires roof jacks to work on.
- 12/12 — 45° angle. The steepest common residential pitch.
What Is Slope Factor?
The slope factor (also called the roof pitch multiplier) converts flat horizontal area to actual sloped roof area. Multiply your building footprint by the slope factor to get the true roof surface area for material estimation. A 6/12 roof has a slope factor of 1.118 — meaning the actual roof is about 12% larger than the footprint.
Related Resources
This reference is for educational purposes only.