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Roof Pitch Calculator
Convert roof pitch to angle and area multiplier.
How the roof pitch calculator works
Roof pitch is expressed as rise per 12 in of horizontal run. The pitch multiplier used to size rafters and sheathing is √(1 + (rise/run)²). Angle in degrees = arctan(rise / run).
Frequently asked questions
What is a 6:12 roof pitch in degrees?
26.6° — the arctan of 6/12. A 4:12 is 18.4°, 8:12 is 33.7°, and 12:12 is 45°.
What is the pitch multiplier used for?
Multiply the flat (footprint) area by this factor to get the true sloped roof area for shingles and sheathing.
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