A roofing square is 100 square feet of roof surface, a 10 × 10 ft area. Most standard asphalt shingles, both 3-tab and architectural, come three bundles to a square, so each bundle covers about 33⅓ sq ft. Some heavier specialty shingles need four or five bundles per square. Always check the coverage printed on the bundle, and add 10 to 15% for waste.
The roofing calculator converts your house footprint and roof pitch into roof area, squares and bundles.
What is a roofing square?
Roofers price and order by the square because it keeps the numbers small: a typical house roof is 15 to 30 squares rather than 1,500 to 3,000 square feet. The square measures the actual sloped roof surface, not the floor area of the house. A steeper roof over the same footprint has more squares.
How shingle bundles are packaged
| Shingle type | Bundles per square | Coverage per bundle |
|---|---|---|
| Most 3-tab and architectural shingles | 3 | About 33⅓ sq ft |
| Some heavier designer lines (example: GAF Woodland) | 4 | About 25 sq ft |
| Some specialty shingles | Up to 5 | About 20 sq ft |
Bundles are kept to a weight one person can carry up a ladder, so heavier shingles come in more, smaller bundles. That is why the bundles-per-square number belongs to the product, not to roofing in general.
Why bundle coverage varies by product
- Weight. Thick, layered shingles weigh more per square, so each bundle covers less.
- Shingle size and exposure. The visible part of each shingle (the exposure) sets how many shingles a square needs.
- Accessories. Starter strips, hip and ridge caps are sold as separate products with their own coverage, measured in linear feet.
Roof pitch, waste, hips and valleys
- Pitch. Multiply the footprint by the pitch factor to get the real roof area. An 8/12 roof has a factor of about 1.20, so a 1,200 sq ft footprint carries about 1,442 sq ft of roof.
- Waste. GAF suggests adding 10 to 15% for trim and waste. Simple gable roofs sit at the low end; hips, valleys and dormers push it up.
- Hips and valleys mean angled cuts along their whole length, and the offcuts are rarely usable.
From roof area to bundles
| Roof area | Squares | 3 bundles/sq (+10%) | 4 bundles/sq (+10%) | 5 bundles/sq (+10%) |
|---|---|---|---|---|
| 1,000 sq ft | 10 | 33 | 44 | 55 |
| 1,500 sq ft | 15 | 50 | 66 | 83 |
| 2,000 sq ft | 20 | 66 | 88 | 110 |
| 2,500 sq ft | 25 | 83 | 110 | 138 |
Worked roof material estimate
- Footprint. A house measures 40 × 30 ft including overhangs: 1,200 sq ft.
- Pitch. The roof is 8/12, factor 1.202: 1,200 × 1.202 = 1,442 sq ft, or 14.42 squares.
- Bundles. With a 3-bundle shingle and 10% waste: 14.42 × 3 × 1.10 = 47.6, so 48 bundles. As a hip roof with 15% waste: 50 bundles.
- Different product. With a 4-bundle designer shingle and 10% waste: 64 bundles.
- Accessories. Measure the eaves and rakes for starter strip, and the ridges and hips for cap shingles, and order them separately.
Working on a roof is dangerous. Measure from the ground and from plans where you can, and use fall protection if you go up. For how the pitch factor works, see the formula on the roofing calculator page.
Sources
- GAF: How Many Bundles of Shingles Are in a Square? (roofing square, bundles per square, waste factor)
