Roofing Shingle Calculator
Enter your roof's footprint and pitch to get the number of roofing squares, the shingle bundles to buy (three bundles cover one square), and the material cost — with a waste allowance built in for cuts and caps.
Common sizes
Jump to a pre-filled estimate:
How it works
Roof area = footprint × pitch factor. One roofing square = 100 sq ft, and standard architectural shingles come three bundles to a square. We add your waste allowance, then round bundles up (you can't buy a partial bundle).
The formula
Squares = (Length × Width × pitch ÷ 100) × (1 + waste%). Bundles = ceil(squares × 3). Cost = bundles × price per bundle.
Worked examples
| Example | Result |
|---|---|
| 40×30 roof, medium pitch | About 15.5 squares — 47 bundles, roughly $1,645 in shingles. |
| 50×40 roof, steep pitch | A large steep roof: about 88 bundles. |
Frequently asked questions
How many bundles of shingles per square?
Standard architectural (dimensional) shingles come three bundles to a square (100 sq ft). Heavier or premium shingles can be four bundles per square.
How many bundles of shingles do I need?
Multiply your roofing squares by three, then round up and add 10–15% for waste. This tool does it automatically once you enter your roof size and pitch.
How much does a bundle of shingles cost?
Asphalt shingle bundles typically run $30–$45 each depending on brand and line, so a square costs roughly $100–$135 in material. Enter your local price for an accurate total.
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Method reviewed by The editorial team. See our methodology for sources and assumptions.