Roof Pitch Calculator

What it is

Roof Pitch Calculator is a free online tool for calculating roof pitch and related measurements. Users enter rise and run, an angle in degrees, or a pitch ratio to instantly calculate roof pitch, slope percentage, and rafter length. The tool provides reference charts of common roof pitches with their angles, slopes, and rafter multipliers. It is designed for informational and educational purposes to assist with general roof pitch estimation and related measurements.

Questions from the bench

What is roof pitch?

Roof pitch is the measure of a roof's steepness, expressed as a ratio of vertical rise to horizontal run. It tells you how much the roof rises vertically for every 12 inches it runs horizontally. Roof pitch affects drainage, the choice of roofing materials, attic space, and the overall architectural character of a building.

How do I calculate roof pitch?

To calculate roof pitch, you need two measurements: rise (how much the roof goes up) and run (the horizontal distance). Divide the rise by the run, then multiply by 12 to get the pitch in the standard X:12 format. Alternatively, use the tangent function — tan(angle) × 12 gives you the pitch ratio.

What is a good roof pitch for a house?

The most common residential roof pitch in the United States is 4:12 to 9:12. A 6:12 pitch is often considered the sweet spot — it provides excellent drainage, works with almost all roofing materials including asphalt shingles, metal roofing, and wood shakes, and creates attractive curb appeal without making installation prohibitively expensive.

How do I convert roof pitch to degrees?

To convert a roof pitch ratio to degrees, use the arctangent (inverse tangent) function: Degrees = atan(pitch ÷ 12) × (180 ÷ π). For example, a 6:12 pitch equals 26.57°, and a 12:12 pitch equals exactly 45°.