What is roof pitch?
Roof pitch is how many inches a roof rises for every 12 inches of horizontal run. A roof that rises 6 in over 12 in is a 6/12 pitch: a 26.6° angle, a 50% slope and a pitch factor of 1.118.
How to measure roof pitch
- Hold a level horizontally with one end touching the roof surface or the underside of a rafter.
- Mark the level at 12 in from the end touching the roof.
- Measure straight up or down from that mark to the roof. That distance is the rise per 12 in.
- Enter the rise and a run of 12 in. If you measured over a different run, enter that run instead.
Roof pitch to degrees
| Pitch | Angle | Slope | Pitch factor |
|---|---|---|---|
| 2/12 | 9.5° | 16.7% | 1.014 |
| 3/12 | 14.0° | 25.0% | 1.031 |
| 4/12 | 18.4° | 33.3% | 1.054 |
| 5/12 | 22.6° | 41.7% | 1.083 |
| 6/12 | 26.6° | 50.0% | 1.118 |
| 7/12 | 30.3° | 58.3% | 1.158 |
| 8/12 | 33.7° | 66.7% | 1.202 |
| 9/12 | 36.9° | 75.0% | 1.250 |
| 10/12 | 39.8° | 83.3% | 1.302 |
| 12/12 | 45.0° | 100.0% | 1.414 |
How the calculator works
Pitch = rise ÷ run × 12, written as x/12
Angle = arctan(rise ÷ run)
Slope = rise ÷ run × 100%
Pitch factor = √(1 + (rise ÷ run)²)
The pitch factor converts a flat footprint into sloped roof area. Use it with the roofing calculator to estimate squares and bundles of shingles.
Frequently asked questions
What is a 4/12 roof pitch in degrees?
A 4/12 pitch is about 18.4 degrees. It rises 4 inches for every 12 inches of run, a slope of 33.3%.
What is a 6/12 roof pitch in degrees?
A 6/12 pitch is about 26.6 degrees, a 50% slope. Its pitch factor is 1.118, so the roof surface is about 11.8% larger than the footprint.
How do I convert degrees to roof pitch?
Multiply 12 by the tangent of the angle. For example, a 30 degree roof has a rise of 12 × tan(30°) = 6.93, about a 7/12 pitch.
Is roof pitch the same as roof slope?
They describe the same steepness in different units. Pitch is written as rise per 12 inches of run, while slope is often written as a percentage or an angle.