How do I calculate roofing squares and shingle bundles from roof pitch?
Roof surface = footprint × pitch factor. Roofing squares = surface area ÷ 100 sq ft. Bundles = squares × bundles per square, with waste added and rounded up.
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Roof shingles calculator
Estimate roofing squares, shingle bundles, and installation waste by area and pitch.
- Metric and imperial units
- Instant updates as inputs change
- Data is calculated in this browser only
Results are planning estimates. Confirm site dimensions, product specifications, and installation waste before purchasing.
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Calculation notes
Understand the Roof shingles calculator
Roof footprint is multiplied by a pitch factor to estimate surface area. Each 100 sq ft is one roofing square, then bundles per square and waste determine the order quantity.
How many shingle bundles cover a 40 by 30 ft roof with a 6:12 pitch?
A 40 × 30 ft footprint with a 6:12 pitch has about 1,342 sq ft of roof surface. With 10% waste and 3 bundles per square, order about 45 bundles.
Which roofing materials should be estimated separately from field shingles?
- Count each roof plane and use the actual pitch.
- Estimate ridge caps, starters, underlayment, flashing, and valley material separately.
How do hips, valleys, dormers, and waste affect shingle quantity?
- Defaults follow common U.S. asphalt-shingle packaging.
- Ridge caps, valleys, starter strips, and underlayment should be estimated separately.
- Dormers, hips, valleys, tear-off damage, bundle coverage, and local code affect the final order.
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