A 6/12 roof rises 6 inches for every 12 inches it runs. Enter 6.
Formula: degrees = arctan(rise / 12). Pitch from degrees = 12 x tan(angle).
Standard asphalt shingle slope: one layer of underlayment under the IRC.
6/12 pitch in degrees
26.57degrees
- Angle
- 26.57 degrees
- Pitch
- 6.00 / 12
- Slope factor (area multiplier)
- 1.118
- Hip and valley factor
- 1.500
- Percent grade
- 50.0%
- Rafter length per foot of run
- 13.42 in
- OSHA roof class
- Steep (over 4/12)
Chart
Roof pitch to degrees chart
Every pitch from 1/12 to 24/12, with the multipliers for roof area and for hip and valley length.
| Pitch | Degrees | Slope factor | Hip / valley factor | Grade |
|---|---|---|---|---|
| 1/12 | 4.76 | 1.003 | 1.417 | 8.3% |
| 2/12 | 9.46 | 1.014 | 1.424 | 16.7% |
| 3/12 | 14.04 | 1.031 | 1.436 | 25.0% |
| 4/12 | 18.43 | 1.054 | 1.453 | 33.3% |
| 5/12 | 22.62 | 1.083 | 1.474 | 41.7% |
| 6/12 | 26.57 | 1.118 | 1.500 | 50.0% |
| 7/12 | 30.26 | 1.158 | 1.530 | 58.3% |
| 8/12 | 33.69 | 1.202 | 1.563 | 66.7% |
| 9/12 | 36.87 | 1.250 | 1.601 | 75.0% |
| 10/12 | 39.81 | 1.302 | 1.641 | 83.3% |
| 11/12 | 42.51 | 1.357 | 1.685 | 91.7% |
| 12/12 | 45.00 | 1.414 | 1.732 | 100.0% |
| 13/12 | 47.29 | 1.474 | 1.781 | 108.3% |
| 14/12 | 49.40 | 1.537 | 1.833 | 116.7% |
| 15/12 | 51.34 | 1.601 | 1.887 | 125.0% |
| 16/12 | 53.13 | 1.667 | 1.944 | 133.3% |
| 17/12 | 54.78 | 1.734 | 2.002 | 141.7% |
| 18/12 | 56.31 | 1.803 | 2.062 | 150.0% |
| 19/12 | 57.72 | 1.873 | 2.123 | 158.3% |
| 20/12 | 59.04 | 1.944 | 2.186 | 166.7% |
| 21/12 | 60.26 | 2.016 | 2.250 | 175.0% |
| 22/12 | 61.39 | 2.088 | 2.315 | 183.3% |
| 23/12 | 62.45 | 2.162 | 2.382 | 191.7% |
| 24/12 | 63.43 | 2.236 | 2.449 | 200.0% |
How it works
Measuring pitch and using the numbers
Measuring pitch on the roof. Hold a level flat against the roof, mark 12 inches along it, and measure straight down from that mark to the roof surface. The inches you read are the rise, so 7 inches means a 7/12 pitch. From the attic, do the same against the underside of a rafter.
Measuring the angle instead. A phone level or an angle finder on the roof gives degrees. Switch the calculator to degrees and it returns the pitch, plus the nearest whole pitch you would write on an estimate.
Slope factor. Multiply the flat footprint (or the flat run of a rafter) by the slope factor to get the true sloped area or length. This is how a measured footprint becomes roofing squares.
Hip and valley factor. For two roof planes of the same pitch meeting at a square corner, multiply the common rafter run by this factor to get the length of the hip or valley. At 6/12 it is 1.5, so a 14 foot run gives a 21 foot hip.
Questions
What roofers ask about this
How many degrees is a 4/12 roof pitch?
What is a 6/12 pitch in degrees?
What roof pitch is 45 degrees?
What is the slope factor used for?
Is a roof over 4/12 a steep roof?
What is the lowest pitch for asphalt shingles?
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