Roof Pitch Calculator
Express a roof slope as x-in-12 pitch and degrees, with the slope factor.
What is Roof Pitch?
Roof pitch is written as x-in-12: how many inches the roof climbs per 12 inches of horizontal run. '7:12' means 7 inches of rise per foot. The same fact is an angle — 7:12 is 30.26° — and the two get mixed up constantly. Pitch decides materials (below 2:12 needs membrane, not shingles), walkability, and the slope factor that turns a footprint into shingle area.
How it works
The rise-over-run ratio is scaled to a 12-inch run for the conventional notation, and the angle is arctan(rise ÷ run). The slope factor (1 ÷ cos of the angle) is shown because it is exactly what the Roof Area Calculator applies — one multiplication, no second opinion about the geometry.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.