How to Use This Roof Pitch Calculator
The tool turns two simple measurements into every figure a roofer, builder or DIY homeowner needs. Follow these three steps.
Type the vertical rise into the first box and the horizontal run into the second. Run is traditionally measured over a 12-inch span, so a roof that climbs 6 inches across that span is a 6:12 pitch.
The results panel shows the pitch as a ratio, the angle in degrees, the slope as a percentage and the roof pitch multiplier all at once, so you do not need a separate roof pitch angle calculator.
Add your building footprint area to estimate the finished roof surface area for ordering shingles, felt or metal sheeting.
What Is Roof Pitch?
Roof pitch is the measure of how steep a roof is. It is one of the most important numbers in any roofing project because it affects drainage, the material you can use, the cost and even the look of the building.
Pitch is most commonly written as rise over run — the vertical height the roof gains for a given horizontal distance. A 6:12 roof rises 6 inches for every 12 inches travelled horizontally. This ratio is the foundation of every calculation on this page.
Traditional Definition: Rise Over Span
In traditional usage, pitch meant rise divided by the full span of the building, while slope meant rise divided by run (half the span).
Modern Usage: Why the Terms Are Used Interchangeably
Today most builders, calculators and manufacturers treat pitch and slope as the same thing and base both on rise over run. This calculator follows that modern, rise-over-run convention.