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Roof Pitch Calculator
A roof's pitch from its rise and run: x in 12, the angle, the slope and the rafter multiplier.
Result…
How it's calculated
Pitch = 12 × rise ÷ run (x in 12) Angle = atan(rise ÷ run) Slope % = rise ÷ run × 100 Rafter multiplier = √(1 + (rise ÷ run)²)
Turns a roof's rise and run into the pitch roofers use (inches of rise per 12 of run), the angle in degrees and the slope as a percentage. Multiply a horizontal run by the rafter multiplier to get the length along the slope, which also scales a plan area up to the true roof area.
Your numbers, step by step
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