Degrees to roof pitch
Pitch = tan(angle) × 12. The multiplier is 1 ÷ cos(angle), the factor that turns flat area into roof area. A phone level gives degrees, so find the nearest row.
| Angle | Pitch | Percent slope | Area multiplier |
|---|---|---|---|
| 1° | 0.21/12 | 1.7% | 1.000 |
| 2° | 0.42/12 | 3.5% | 1.001 |
| 3° | 0.63/12 | 5.2% | 1.001 |
| 4° | 0.84/12 | 7.0% | 1.002 |
| 5° | 1.05/12 | 8.7% | 1.004 |
| 6° | 1.26/12 | 10.5% | 1.006 |
| 7° | 1.47/12 | 12.3% | 1.008 |
| 8° | 1.69/12 | 14.1% | 1.010 |
| 9° | 1.90/12 | 15.8% | 1.012 |
| 10° | 2.12/12 | 17.6% | 1.015 |
| 11° | 2.33/12 | 19.4% | 1.019 |
| 12° | 2.55/12 | 21.3% | 1.022 |
| 13° | 2.77/12 | 23.1% | 1.026 |
| 14° | 2.99/12 | 24.9% | 1.031 |
| 15° | 3.22/12 | 26.8% | 1.035 |
| 16° | 3.44/12 | 28.7% | 1.040 |
| 17° | 3.67/12 | 30.6% | 1.046 |
| 18° | 3.90/12 | 32.5% | 1.051 |
| 19° | 4.13/12 | 34.4% | 1.058 |
| 20° | 4.37/12 | 36.4% | 1.064 |
| 21° | 4.61/12 | 38.4% | 1.071 |
| 22° | 4.85/12 | 40.4% | 1.079 |
| 23° | 5.09/12 | 42.4% | 1.086 |
| 24° | 5.34/12 | 44.5% | 1.095 |
| 25° | 5.60/12 | 46.6% | 1.103 |
| 26° | 5.85/12 | 48.8% | 1.113 |
| 27° | 6.11/12 | 51.0% | 1.122 |
| 28° | 6.38/12 | 53.2% | 1.133 |
| 29° | 6.65/12 | 55.4% | 1.143 |
| 30° | 6.93/12 | 57.7% | 1.155 |
| 31° | 7.21/12 | 60.1% | 1.167 |
| 32° | 7.50/12 | 62.5% | 1.179 |
| 33° | 7.79/12 | 64.9% | 1.192 |
| 34° | 8.09/12 | 67.5% | 1.206 |
| 35° | 8.40/12 | 70.0% | 1.221 |
| 36° | 8.72/12 | 72.7% | 1.236 |
| 37° | 9.04/12 | 75.4% | 1.252 |
| 38° | 9.38/12 | 78.1% | 1.269 |
| 39° | 9.72/12 | 81.0% | 1.287 |
| 40° | 10.07/12 | 83.9% | 1.305 |
| 41° | 10.43/12 | 86.9% | 1.325 |
| 42° | 10.80/12 | 90.0% | 1.346 |
| 43° | 11.19/12 | 93.3% | 1.367 |
| 44° | 11.59/12 | 96.6% | 1.390 |
| 45° | 12.00/12 | 100.0% | 1.414 |
| 50° | 14.30/12 | 119.2% | 1.556 |
| 55° | 17.14/12 | 142.8% | 1.743 |
| 60° | 20.78/12 | 173.2% | 2.000 |
The angles that match a whole pitch
Whole-number pitches fall on awkward angles. Here is each, so you can read a phone app and recognize the pitch:
| Pitch | Exact angle | Round to |
|---|---|---|
| 1/12 | 4.76° | 5° |
| 2/12 | 9.46° | 9° |
| 3/12 | 14.04° | 14° |
| 4/12 | 18.43° | 18° |
| 5/12 | 22.62° | 23° |
| 6/12 | 26.57° | 27° |
| 7/12 | 30.26° | 30° |
| 8/12 | 33.69° | 34° |
| 9/12 | 36.87° | 37° |
| 10/12 | 39.81° | 40° |
| 11/12 | 42.51° | 43° |
| 12/12 | 45.00° | 45° |
How to use the chart
- Measure the angle of a rafter or the roof surface with a phone or angle finder.
- Find the nearest row. Between rows, use the closest pitch.
- Use the multiplier for area: a 1,500 sq ft footprint at 30 degrees is 1,500 × 1.155 = 1,732 sq ft of roof.
Rounding is the risk. One degree changes 5/12 (22.6°) to 6/12 (26.6°) territory, so for ordering materials measure the rise and run directly. See how to measure roof pitch. The roof pitch calculator accepts an angle and shows the exact pitch, and how to calculate roof pitch shows the formula.
Frequently asked questions
How many degrees is a 6/12 pitch?
26.57 degrees.
What pitch is 30 degrees?
6.93/12, which is close to 7/12.
What angle is a 4/12 roof?
18.43 degrees.