Key takeaways
- Bundles = roof squares, including waste, × bundles per square.
- Most asphalt shingles use 3 bundles per square, but some products use up to 5.
- GAF suggests adding 10–15% for trim and waste.
Enter your roof area, not your floor area. If you don't have it yet, start with the roof area calculator.
How the calculator works
- Squares: roof area ÷ 100 × (1 + waste %)
- Bundles: squares × bundles per square, rounded up
Worked example
Take GAF's example of a 2,400-square-foot roof, with a 10% waste allowance and 3 bundles per square:
- 2,400 ÷ 100 = 24 squares
- 24 × 1.10 = 26.4 squares
- 26.4 × 3 = 79.2, which rounds up to 80 bundles
Without any waste allowance, it would be 72 bundles.
Choosing a waste allowance
GAF suggests adding 10–15% for trim and waste, and says steep slopes and features like valleys, rakes and dormers call for more material. We default to 10% as a starting point:
- Toward the lower end: a simple roof with few cuts
- Toward the higher end or above: hips, valleys, dormers and steep slopes
These are planning figures, and a roofer's measured takeoff should replace them.
Check bundles per square on the product
GAF says most standard asphalt shingles come in three bundles per square, while some specialty shingles can take up to five. For example, its Timberline HDZ uses three, and its Woodland line uses four. Coverage is printed on the package, so use that figure if it differs.
What this doesn't count
Shingles are only part of a roof. Your order may also need:
- Starter strips and ridge caps
- Underlayment, plus ice barrier where required
- Drip edge and flashing
- Nails and ventilation
Ask your supplier what the product's installation instructions require. Low slopes also have extra rules.
How the waste allowance changes your order
For a 2,000-square-foot roof at 3 bundles per square:
| Waste | Squares | Bundles |
|---|---|---|
| 0% | 20.0 | 60 |
| 5% | 21.0 | 63 |
| 10% | 22.0 | 66 |
| 15% | 23.0 | 69 |
| 20% | 24.0 | 72 |
Each 5% adds 3 bundles here. Use that to judge whether your supplier's takeoff looks reasonable.
Frequently asked questions
How many bundles do I need for 1,000 square feet of roof?
At 3 bundles per square, that's 30 bundles before waste, or 33 with a 10% allowance.
Should I round up?
Yes. Bundles are sold whole, and a small surplus is useful for cuts and later repairs. Ask whether your supplier takes back unopened bundles.
Can I use my home's square footage?
No. Roof area is usually larger than the footprint and has little to do with living area on a multi-story home.
Sources
We use primary sources where we can: building codes, federal rules and manufacturer documents. Read our editorial standards.