Home › Tools › Roof pitch › 8/12

8/12 roof pitch in degrees

A 8-in-12 roof — 8 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.

8/12 pitch =

=33.69°

Angle

33.69°

Percent grade

66.66667%

Slope ratio

0.666667

Rafter / ft of run

1' 2-7/16"

What it means on the roof

Set a speed square to 33.69° for the plumb and seat cuts. Every foot of horizontal run adds 1' 2-7/16" of common-rafter length, so a run of 10 ft makes a rafter about ten times that. The percent grade (66.66667%) is the same slope a road sign or a laser level reads.

Nearby pitches

Pitches around 8/12

Pitch	Angle	Grade	Rafter / ft run
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"
8/12	33.69°	66.66667%	1' 2-7/16"
9/12	36.87°	75%	1' 3"
10/12	39.81°	83.33333%	1' 3-5/8"
11/12	42.51°	91.66667%	1' 4-1/4"

All roof pitches Open the calculator

The same math, offline

Every calc, on your tape measure — even with no signal.

TapeMath for iPhone runs this exact engine offline, adds rafters, stairs, studs, pitch and a paperless tape, and the key layout your thumbs already know. $9.99 once — no subscription, ever.

See the app

Coming soon — TapeMath is in final App Review. Meanwhile, use the free web calculator →