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4/12 roof pitch in degrees

A 4-in-12 roof — 4 inches of rise for every 12 inches of run — as an angle, a percent grade, a slope ratio, and the rafter length it adds per foot of run.

4/12 pitch =

=18.43°

Angle

18.43°

Percent grade

33.33333%

Slope ratio

0.333333

Rafter / ft of run

1' 0-5/8"

What it means on the roof

Set a speed square to 18.43° for the plumb and seat cuts. Every foot of horizontal run adds 1' 0-5/8" of common-rafter length, so a run of 10 ft makes a rafter about ten times that. The percent grade (33.33333%) is the same slope a road sign or a laser level reads.

Nearby pitches

Pitches around 4/12

Pitch	Angle	Grade	Rafter / ft run
1/12	4.76°	8.333333%	1' 0-1/16"
2/12	9.46°	16.66667%	1' 0-3/16"
3/12	14.04°	25%	1' 0-3/8"
4/12	18.43°	33.33333%	1' 0-5/8"
5/12	22.62°	41.66667%	1' 1"
6/12	26.57°	50%	1' 1-7/16"
7/12	30.26°	58.33333%	1' 1-7/8"

All roof pitches Open the calculator

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