Roofing squares calculator
Roofing squares and bundles from roof area.
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How it's calculated
The footprint, length times width measured from the ground including the overhangs, is multiplied by a pitch factor to get the true sloped area. The factor is the length of the slope per foot of run: 1.118 for a 6/12 pitch, 1.414 for 12/12. Waste for cuts, ridges and starter rows is added, and the total is divided by 100, since roofers sell and price shingles by the “square” of 100 square feet. Bundles are squares times bundles per square, usually three.
What is a roofing square?
One hundred square feet of roof surface. Shingles, underlayment and labour are all quoted per square. A 2,000 sq ft roof is 20 squares, about 60 bundles of shingles.
How do I find my roof pitch?
Hold a level horizontally against the roof or a rafter in the attic, measure 12 in along it, then measure down to the surface. That drop in inches is the pitch: 6 in means 6/12. Most houses are between 4/12 and 9/12.
How much waste should I add?
About 10% for a plain gable roof, 15% when there are hips, valleys, dormers or skylights, since every cut edge wastes part of a shingle. Starter strips and ridge caps are extra; many brands sell those separately.
Results are estimates for informational purposes only and are not financial, medical or legal advice.