Many people dont know what we mean by roof pitch. Pitch is the angle of the roof, however, rather than show an angle roofers use whats known as pitch. This is the amount the roof rises for a foot of horizontal length. So if you measured out a foot, then measured up to the roof line, you would get a rise number in inches. This is the pitch. For instance, if you measured out a foot, then up and you measured 4 inches, thats a 4 pitch, or sometimes called a 4/12 pitch. If you measured 8 inches that would be an 8/12 pitch.