📐Roof Pitch Calculator

Roof pitch indicates the steepness (slope) of a roof. It’s typically expressed as a ratio of the vertical rise to the horizontal run, like “6/12”, or as an angle in degrees.

Rise is the vertical distance the roof elevates from the lowest point of the measured run to the highest point of that same run.

Run is the horizontal distance over which the rise is measured. For standard X/12 pitch notation, the run is typically 12 inches.

Using a 12-inch run provides a standardized way to compare roof steepness. A “6/12 pitch” means for every 12 inches horizontally, the roof rises 6 inches vertically.

Generally: Low-slope: Pitches less than 3/12 or 4/12. May require special roofing materials. Conventional slope: Between 4/12 and 9/12. Steep-slope: Pitches greater than 9/12. May require extra safety precautions and installation techniques.

The angle (in degrees) = arctan(rise / run). This calculator does that for you.

Pitch affects material choices (some shingles aren’t suitable for very low or very steep slopes), drainage, snow/water runoff, attic ventilation, construction complexity, and overall building aesthetics.

Yes. You can use a level and a tape measure. Place a 12-inch level horizontally against the roof slope. Measure the vertical distance from the end of the level up to the roof surface; this is your rise for a 12-inch run.

Yes. Steeper roofs are often more difficult and dangerous to work on, potentially increasing labor costs. Some materials for steep slopes might also be more expensive.

The pitch factor (or slope factor) is a multiplier used to convert a flat, horizontal area (like a building’s footprint) into the actual surface area of a sloped roof. It’s calculated from the rise and run.