Roofing Calculator
Estimate roofing squares, bundles and underlayment.
How the roofing calculator works
Roof area = house footprint × pitch factor. The pitch factor is √(1 + (rise/12)²): a 6:12 roof has a 1.118 factor. A "square" is 100 ft² of roof. Shingles are sold in 3 bundles per square.
Popular uses for the roofing calculator
Roofing for a House
Estimate shingle bundles and squares for a full re-roof.
Roofing for a Garage
Estimate shingle bundles and squares for a garage roof.
Roofing for a Shed
Estimate shingle bundles for a shed roof.
Roofing for a Porch
Estimate materials for a porch or overhang roof.
Roofing for an Addition
Estimate materials for a room-addition roof.
Frequently asked questions
How many bundles of shingles do I need?
3 bundles per roofing square. For a 40×30 ft home with a 6:12 roof: about 13.4 squares × 3 = 41 bundles.
What is a roofing square?
100 ft² of roof surface. Shingles are priced per square and packaged in bundles that cover ~33 ft² each.
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