Roof pitch chart
Every pitch from 1/12 to 24/12 in degrees, percent and rafter factor. Pick one for rise and rafter tables.
| Pitch | Angle | Slope | Rafter factor | Type |
|---|---|---|---|---|
| 1/12 | 4.76° | 8.3% | 1.0035 | Flat / very low slope |
| 2/12 | 9.46° | 16.7% | 1.0138 | Low slope |
| 3/12 | 14.04° | 25% | 1.0308 | Low slope |
| 4/12 | 18.43° | 33.3% | 1.0541 | Conventional |
| 5/12 | 22.62° | 41.7% | 1.0833 | Conventional |
| 6/12 | 26.57° | 50% | 1.118 | Conventional |
| 7/12 | 30.26° | 58.3% | 1.1577 | Conventional |
| 8/12 | 33.69° | 66.7% | 1.2019 | Conventional |
| 9/12 | 36.87° | 75% | 1.25 | Steep |
| 10/12 | 39.81° | 83.3% | 1.3017 | Steep |
| 11/12 | 42.51° | 91.7% | 1.3566 | Steep |
| 12/12 | 45° | 100% | 1.4142 | Steep |
| 13/12 | 47.29° | 108.3% | 1.4743 | Steep |
| 14/12 | 49.4° | 116.7% | 1.5366 | Steep |
| 15/12 | 51.34° | 125% | 1.6008 | Steep |
| 16/12 | 53.13° | 133.3% | 1.6667 | Steep |
| 17/12 | 54.78° | 141.7% | 1.7341 | Steep |
| 18/12 | 56.31° | 150% | 1.8028 | Steep |
| 19/12 | 57.72° | 158.3% | 1.8727 | Steep |
| 20/12 | 59.04° | 166.7% | 1.9437 | Steep |
| 21/12 | 60.26° | 175% | 2.0156 | Steep |
| 22/12 | 61.39° | 183.3% | 2.0883 | Steep |
| 23/12 | 62.45° | 191.7% | 2.1619 | Steep |
| 24/12 | 63.43° | 200% | 2.2361 | Steep |
Pitch is rise over a 12" run. Angle is the same slope in degrees from level, arctan(pitch ÷ 12). Slope % is rise per 100 of run. The rafter factor is how much longer the slope is than its run — multiply a run by it to get the rafter length, or a footprint by it to get the roof area.
To find the pitch from a measurement or an angle, use the roof pitch calculator; to cut the rafters, the rafter calculator.
As inches of rise per 12 inches of run, like 6/12 or 6:12 ("six in twelve"). The chart converts each pitch to degrees and percent.
About 6.93/12 — between a 6/12 (26.6°) and a 7/12 (30.3°) roof. For any angle, use the roof pitch calculator.
Roofers usually call anything over 8/12 or 9/12 steep: it can’t be walked safely without roof jacks or a harness, and labour costs go up.
Below 4/12. Asphalt shingles can go down to 2/12 with double underlayment; below 2/12 you need a membrane or metal rated for low slopes.