Roof Pitch Chart
Every roof pitch from 1/12 to 18/12 with its angle, percent slope, multiplier, hip/valley factor and rafter length per foot of run. Tap a pitch for its own page.
Roof pitch
6/12 pitch
26.6° · 50.0% · ×1.118
6/12 is 26.57°, a 50.0% slope, and the roof is 11.8% larger than its footprint.
- Angle26.57°
- Percent slope50.0%
- Pitch multiplier1.1180
- Hip and valley factor1.5000
- Rafter per foot of run13.42 in
- Slope class (OSHA)Steep (over 4 in 12)
Pitch is rise in inches over 12 inches of run. The multiplier turns a flat measurement into sloped length: multiply the footprint area by it to get roof area.
Planning estimate, not a quote. Disclaimer
Roof pitch, degrees, percent and multiplier
| Pitch | Angle | Percent | Multiplier | Hip/valley | Rafter per ft run | OSHA class |
|---|---|---|---|---|---|---|
| 1/12 | 4.76° | 8.3% | 1.0035 | 1.4167 | 12.04 in | Low slope |
| 2/12 | 9.46° | 16.7% | 1.0138 | 1.4240 | 12.17 in | Low slope |
| 3/12 | 14.04° | 25.0% | 1.0308 | 1.4361 | 12.37 in | Low slope |
| 4/12 | 18.43° | 33.3% | 1.0541 | 1.4530 | 12.65 in | Low slope |
| 5/12 | 22.62° | 41.7% | 1.0833 | 1.4743 | 13.00 in | Steep |
| 6/12 | 26.57° | 50.0% | 1.1180 | 1.5000 | 13.42 in | Steep |
| 7/12 | 30.26° | 58.3% | 1.1577 | 1.5298 | 13.89 in | Steep |
| 8/12 | 33.69° | 66.7% | 1.2019 | 1.5635 | 14.42 in | Steep |
| 9/12 | 36.87° | 75.0% | 1.2500 | 1.6008 | 15.00 in | Steep |
| 10/12 | 39.81° | 83.3% | 1.3017 | 1.6415 | 15.62 in | Steep |
| 11/12 | 42.51° | 91.7% | 1.3566 | 1.6853 | 16.28 in | Steep |
| 12/12 | 45.00° | 100.0% | 1.4142 | 1.7321 | 16.97 in | Steep |
| 13/12 | 47.29° | 108.3% | 1.4743 | 1.7815 | 17.69 in | Steep |
| 14/12 | 49.40° | 116.7% | 1.5366 | 1.8333 | 18.44 in | Steep |
| 15/12 | 51.34° | 125.0% | 1.6008 | 1.8875 | 19.21 in | Steep |
| 16/12 | 53.13° | 133.3% | 1.6667 | 1.9437 | 20.00 in | Steep |
| 17/12 | 54.78° | 141.7% | 1.7341 | 2.0017 | 20.81 in | Steep |
| 18/12 | 56.31° | 150.0% | 1.8028 | 2.0616 | 21.63 in | Steep |
The multiplier is the sloped length for each foot of run; multiply a footprint area by it for roof area. The hip/valley factor does the same for hip and valley rafters. "Rafter per ft run" is the multiplier times 12 inches, the figure printed on framing-square rafter tables (for example 13.42 inches at 6/12 and 16.97 inches at 12/12). Low slope and steep follow OSHA's fall-protection definitions: 4 in 12 or less is low slope.
How to use the chart
- Roof area: footprint × multiplier. A 1,200 sq ft footprint at 8/12 is 1,442 sq ft.
- Rafter length: run in feet × multiplier, or the inches per foot of run column.
- Materials: GAF treats 2:12 as the absolute minimum for shingles and 2:12 to under 4:12 as low slope that needs double underlayment. GAF says most US homes sit between 4:12 and 9:12.
Pitch expressed three ways
Pitch (6/12), angle (26.57°) and percent grade (50%) describe the same slope. Percent is rise ÷ run × 100, so 12/12 is 100%. Some plans give the "rise over a span" fraction, like 1/4 pitch, which means 6/12. The degrees chart converts the other way.
Frequently asked questions
What is the most common roof pitch?
GAF says most residential roofs in the US fall between 4:12 and 9:12. Within that range, 4/12 to 8/12 pitches are the ones people search for most on this site.
What is the angle of a 12/12 roof?
45 degrees, a 100% slope with a multiplier of 1.4142.
How many degrees is a 4/12 pitch?
18.43 degrees, a 33.3% slope.
What roof pitch is considered steep?
OSHA calls any roof over 4 in 12 steep and 4 in 12 or less low slope, for fall-protection rules. Roofers often use "steep" for 8/12 and above, but there is no single definition.
What is the minimum pitch for shingles?
GAF gives 2:12 as the absolute minimum for asphalt shingles, with double underlayment between 2:12 and 4:12.
Related
Other roofing calculators
Sources
- OSHA 29 CFR 1926.500: definitions of low-slope and steep roofs (checked Nov 12, 2026)
- GAF: Minimum slope for shingles (checked Nov 12, 2026)
- Swanson Tool: Roof pitch reference (rafter length per foot of run) (checked Nov 12, 2026)