0 sq ft of roof
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Roofing squares
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Shingle bundles (3/sq)
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Pitch multiplier
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Estimated cost
Roof area = footprint × pitch multiplier (√(rise² + 12²) ÷ 12). One roofing “square” is 100 sq ft. Add ~10% for waste and overhangs.
Frequently Asked Questions
How is roof area calculated from pitch?
The flat footprint (length × width) is multiplied by the pitch multiplier √(rise² + 12²) ÷ 12, where “rise” is the roof’s rise per 12 units of run. A steeper roof has more surface area than its footprint.
Calculate roof area, squares and shingle bundles from your building size and roof pitch.