Three bundles cover a roofing square, but you order extra for cuts and ridges. Multiply squares by three, add a waste factor, and round up to whole bundles.
22 squares at 3 bundles each is 66; a 10% waste factor pushes it to 72.6, which rounds up to 73 bundles to order.
The example
Three roofs, each measured in squares with a waste allowance.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | House | Squares | Waste % | Bundles |
| 2 | House A | 22 | 10% | 73 |
| 3 | House B | 30 | 12% | 101 |
| 4 | House C | 18 | 8% | 59 |
The formula
One formula sizes every order:
How it works
From squares to a purchase order:
B2*3converts roofing squares to bundles — three bundles cover one square of standard shingles.(1+C2)adds the waste percentage for cuts, starter, and ridge caps.ROUNDUP(…,0)rounds to whole bundles, because you cannot buy a partial bundle.
Steep or complex roofs need more waste — bump the factor toward 15% for lots of hips and valleys.
Try it: interactive demo
Enter the roof size in squares and a waste factor.
Variations
Different bundle coverage
Some premium shingles run 4 bundles per square — swap the 3.
Pitfalls & errors
Enter waste as a percent (10%) or decimal (0.10); typing 10 would order eleven times too many bundles.
Confirm bundles-per-square on the shingle wrapper — it is usually 3 but not always.
Practice workbook
Frequently asked questions
How many bundles cover a square?
What waste factor should I use?
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