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Roof Pitch Calculator
Convert roof pitch to angle and area multiplier.
How does the roof pitch calculator work?
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).
Which guide explains this in more depth?
- Panel roofs waste differently from shingles: ribs, hips and valleys all change the number you order. Read the metal roofing calculator waste factor guide for the full worked example.
What else do people ask about this calculator?
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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