Roof Pitch Angle and Slope Factor Charts

Roof Pitch is a term describing how steep or flat your roof slope is.  The combination of two numbers are used to display or show the roof pitch.  Two most common methods (4/12 or 4:12) are used for marking the pitch of a roof.  On blue prints architects & engineers usually display the pitch of a roof in the format shown on the image where number (4) represents a rise and number (12) represents a length.  This means if a roof rises 4' in the length of 12', your Roof Pitch would be 4/12 or 18.43 degrees.

Roof Pitch Symbols
Roof Pitch and Corresponding Angles
Roof Pitch (slope) Roof Angle (degree)
1:12 Pitch 4.76°
2:12 Pitch 9.46°
3:12 Pitch 14.04°
4:12 Pitch 18.43°
5:12 Pitch 22.62°
6:12 Pitch 26.57°
7:12 Pitch 30.26°
8:12 Pitch 33.69°
9:12 Pitch 36.87°
10:12 Pitch 39.81°
11:12 Pitch 42.51°
12:12 Pitch 45.00°
13:12 Pitch 47.29°
14:12 Pitch 49.40°
15:12 Pitch 51.34°
16:12 Pitch 53.13°
Slope Factor Chart 1:12 pitch - 6:12 pitch
Pitch of Roof 1:12 2:12 3:12 4:12 5:12 6:12
Slope Factor 1.0035 1.0138 1.0308 1.0541 1.0833 1.1180
Valley & Hip Factor 1.4167 1.4240 1.4362 1.4530 1.4743 1.5000
Slope Factor Chart 7:12 pitch - 12:12 pitch
Pitch of Roof 7:12 8:12 9:12 10:12 11:12 12:12
Slope Factor 1.1577 1.2019 1.2500 1.3017 1.3566 1.4142
Valley & Hip Factor 1.5298 1.5635 1.6008 1.6415 1.6853 1.7320

(A) x (Hip or Valley Factor) = (B)
A) x (Slope Factor) = (B)

Slope Factor Chart