Use this roof pitch calculator to convert rise and run into a common “X-in-12” pitch, roof angle and slope multiplier. The multiplier can be used with a horizontal footprint estimate when planning roof area.
What Roof Pitch Means
Roof pitch describes vertical rise relative to horizontal run. A 6-in-12 roof rises 6 inches for every 12 inches of horizontal run. Steeper roofs have a larger slope multiplier and therefore more roof surface area than the horizontal footprint alone.
Using the Slope Multiplier
Multiply a simple horizontal roof footprint by the slope multiplier to estimate sloped roof area. Complex roofs with valleys, hips, dormers, additions or multiple pitches need section-by-section measurement.
Planning Only
This calculator is for planning and educational use. Field measurements, roof geometry and construction details should be confirmed before ordering materials or preparing a contract estimate.
Next, use the Roof Area Calculator or return to Roofing Calculators & Tools.