Calculator
Roof Square Calculator
Convert your roof measurements into squares and shingle bundles, with a waste allowance included.
Model reviewed August 2026
Roofing squares needed
14.8
Includes 10% waste
- Roof area
- 1,344 sq ft
- Shingle bundles
- 45 bundles
- Underlayment rolls (4 sq)
- 4 rolls
Estimates only. Local pricing, site conditions and code requirements change the real number.
The formula
Squares = (length x width x pitch multiplier) / 100; Bundles = squares x 3 x (1 + waste)
Three bundles of standard architectural shingles cover one square. Add 10% waste for a simple gable roof and up to 15% for a cut-up roof with many valleys.
Worked example
A 40 ft x 30 ft footprint at 6:12 pitch is 1,344 sq ft of roof, or 13.4 squares — about 45 bundles with 10% waste.
Frequently asked questions
What is a roofing square?
A roofing square is 100 square feet of roof surface. Roofers quote materials and labor per square rather than per square foot.
How many bundles of shingles in a square?
Three bundles cover one square for most 3-tab and architectural shingles. Heavier designer shingles can take four or five bundles per square.
Sources
Sources & verification
- NRCA roofing installation standards
- ASTM shingle and underlayment specifications
- International Residential Code — roof assemblies (R905)
- International Code Council (IRC/IBC)
Model vintage August 2026. The links above are the issuing agencies' own pages — we publish them so you can confirm the current rule yourself, not as evidence that each fact on this page was re-checked with them today. Cost figures are modeled estimates based on national baselines adjusted for local labor and material pricing, not quotes. Permit rules change; confirm with the building department before starting work.