Go To Roof Pitch Chart Page The pitch of a roof refers to the angle of its incline, calculated by dividing its vertical rise by its horizontal span, also known as the "run." This concept is similar to what's known as "slope" in geometry and stair design and aligns with the tangent function in trigonometry. In systems that use imperial measurements, the pitch is usually expressed by stating the vertical rise first and the horizontal run second. The horizontal run is standardized at 12 inches, establishing a ratio that indicates how many inches the roof rises for every 12 inches of horizontal distance. Common ratios include 3:12, 4:12, and 5:12, representing the incline's steepness. For digital modeling, architects and designers often convert this pitch into a degree angle to input into computer programs.
