Asphalt shingles
Roof Shingle Calculator USA 2026
Roof area = footprint × pitch multiplier, divided by 100 to get squares, then 3 bundles per square plus 10% for hips, valleys and starter course.
Reviewed by BuildMate Editorial Team Construction Researchers Updated March 2026 2 min read Fact-checked
Roof Calculator — instant results
Results update as you type
Roof area1344 sq ft
Squares13.4
Shingle bundles41
Underlayment rolls (400 sq ft)4
Show calculation steps
- Footprint = 40 × 30 = 1200 sq ft
- Roof area = 1200 × 1.12 = 1344 sq ft
- Squares = 1344 ÷ 100 = 13.44
- Bundles = ⌈13.44 × 3⌉ = 41
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How the asphalt shingles math works
Roof area = footprint × pitch multiplier, divided by 100 to get squares, then 3 bundles per square plus 10% for hips, valleys and starter course.
Roof Area = Footprint × Pitch Multiplier → Squares = Area ÷ 100
Frequently asked questions
How many bundles per square?
Three bundles of architectural shingles = one square (100 sq ft).
Estimates based on 2026 RSMeans USA data and national material averages. Always confirm quantities with your supplier or contractor before ordering.