7/12 roof pitch: 30.26 degrees
A 7/12 roof pitch is 30.2564° to four places. Its multiplier, or rafter factor, is 1.157704, its grade is 58.33% and its slope ratio is 1 : 1.7143.
Change the pitch
30.2564°≈
Multiply your run by 1.157704 for the rafter length. Hips and valleys at this pitch are in the app.
Rafter length at 7/12, by span
Run is half the span on a symmetrical gable. Length is along the rafter, before any birdsmouth, ridge or tail is taken off.
| Building span | Run | Rafter length | Decimal feet |
|---|---|---|---|
| 20 ft | 10 ft | 11' 6-15/16" | 11.577 ft |
| 24 ft | 12 ft | 13' 10-11/16" | 13.892 ft |
| 28 ft | 14 ft | 16' 2-1/2" | 16.208 ft |
| 32 ft | 16 ft | 18' 6-1/4" | 18.523 ft |
| 36 ft | 18 ft | 20' 10-1/16" | 20.839 ft |
Every row is the run multiplied by 1.157704, the rafter factor for 7/12. The multiplier for every pitch is on the roof pitch multiplier table.
What 7/12 means on the roof
Seven in twelve is the closest any whole-number pitch comes to a round 30°, at 30.2564°, and it is the one crews argue about. Six is walkable and eight is not, so 7/12 is where the boots-or-jacks decision actually gets made, and two roofers will price the same roof differently because of it.
The working is the arctangent of the rise over the run: atan(7 ÷ 12) = 30.2564°. The rafter factor is the hypotenuse of the same triangle over its base, √(12² + 7²) ÷ 12, which is why multiplying any run by 1.157704 gives the rafter. That figure is the roof pitch multiplier, and it is the same number whatever the size of the roof.
A hip or valley where both roofs are 7/12 runs at 45° across the plan, so it is longer than the common rafter beside it: 1.5298 ft of hip for every foot of common run, which is 15' 3-9/16" over a 10 ft common run against 11' 6-15/16" for the rafter.
Shingle slope limits quoted here are from the IRC, the United States model code. Your state, province or county may amend them, and several do.
Other pitches: 1/12 · 2/12 · 3/12 · 4/12 · 4.5/12 · 5/12 · 6/12 · 6.5/12 · 8/12 · 9/12 · 10/12 · 11/12 · 12/12. Every pitch from 1/12 to 24/12 is on the roof pitch to degrees chart.
