Roof Pitch Calculator
Calculate roof pitch, angle and slope factor from rise and run.
Assumptions used in this calculation
- Run measured per 12 units: Pitch is expressed as rise per 12 units of run, the standard US roofing convention, regardless of the actual run value entered.
- Simple slope only: The slope factor assumes a single, uniform pitch across the whole roof, complex rooflines with hips, valleys, and multiple pitches need to be broken down and calculated section by section.
About this calculator
Roof slope shows up in three different forms depending on who you're talking to, a roofer might quote a pitch like '6/12,' an architect a slope angle in degrees, and a materials calculator needs a slope factor to convert flat footprint into actual roof area, and converting between them by hand means separate trigonometry each time. This calculator takes your roof's rise and run measurements and computes all three: the pitch ratio expressed per 12 units of run (the standard residential convention), the angle in degrees using the arctangent of rise over run, and the slope factor, the square root of rise squared plus run squared divided by run, which is exactly what you'd multiply a flat footprint area by to get true sloped roof area. Enter rise and run once, and get every common way roof slope gets described back at once. It assumes one uniform pitch across the roof, complex rooflines with hips, valleys or multiple pitches need to be broken into sections and calculated separately.
Worked example
6 in rise over 12 in run
Result: 6/12 pitch, 26.57°
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