4/12 Roof Pitch Calculator
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To calculate the rafter length, input either the Run or the Rise into the calculator and click calculate. The system will automatically compute the rafter length for you.
Note: "4 12 Pitch" typically refers to a slope or pitch of the roof, where 4 inches of rise occurs over 12 inches of run.
4/12 roof pitch multiplier is 1.0541
4/12 pitch roof angle is 18.43 degrees