Bundles per square
How many bundles make a square?
A square is 100 sq ft of roof. Most shingles, including 3-tab and architectural lines, come 3 bundles to the square, so one bundle covers about 33.3 sq ft. Some heavier, designer or impact-rated shingles come 4 or 5 bundles to the square, because each bundle holds fewer or thicker shingles.
The wrapper tells you which one you have. Pick the matching button above and the count changes right away. Never mix up a square (an area) with a bundle (a package): the same roof needs 50 bundles at 3 per square, 66 at 4 and 83 at 5 (1,500 sq ft with 10% extra).
How it works
The formula
squares = roof sq ft × (1 + waste) ÷ 100
bundles = squares × bundles per square, round up
underlayment rolls = roof sq ft ÷ sq ft per roll, round up
starter or ridge bundles = lin ft ÷ lin ft per bundle, round up
Assumptions
- 10% extra for waste on a simple gable roof, 15% with hips and valleys. That covers cuts, mistakes and a few spare shingles for later repairs.
- Pitch factor is sqrt(1 + (rise ÷ 12)²). It turns a flat footprint into the real, sloped roof area.
- Underlayment: a synthetic roll covers 10 squares (1000 sq ft). #15 felt covers about 4 squares and #30 felt about 2; felt coverage varies by brand, so check the roll. We add no waste, since the printed coverage already counts the laps.
- Starter strip is typically 105 lin ft per bundle and ridge cap 33 lin ft. Both vary by product, so read the bundle label and change the number above.
- Metric: square meters are converted to square feet for the math. Shingles are still sold by the bundle, so the shopping list is the same.
Worked example
A 1,500 sq ft roof, 10% extra, 3 bundles per square, synthetic underlayment
- Add 10%: 1,500 × 1.10 = 1,650 sq ft
- In squares: 1,650 ÷ 100 = 16.5 squares
- In bundles: 16.5 × 3 = 49.5, round up to 50 bundles
- Underlayment: 1,500 ÷ 1,000 = 1.5, round up to 2 rolls
- At $40.00 a bundle (the middle of our typical range): 50 × $40.00 = $2,000 for shingles
Common roof sizes
| Roof area | Squares, 10% | Bundles, 10% | Squares, 15% | Bundles, 15% |
|---|---|---|---|---|
| 1,000 sq ft | 11 | 33 | 11.5 | 35 |
| 1,500 sq ft | 16.5 | 50 | 17.25 | 52 |
| 2,000 sq ft | 22 | 66 | 23 | 69 |
| 2,500 sq ft | 27.5 | 83 | 28.75 | 87 |
| 3,000 sq ft | 33 | 99 | 34.5 | 104 |
Sloped roof area, 3 bundles per square. Bundles are rounded up.
Pitch factors
| Pitch | Factor | Roof from 1,500 sq ft footprint |
|---|---|---|
| 4/12 | 1.054 | 1,581 sq ft |
| 6/12 | 1.118 | 1,677 sq ft |
| 8/12 | 1.202 | 1,803 sq ft |
| 10/12 | 1.302 | 1,953 sq ft |
| 12/12 | 1.414 | 2,121 sq ft |
Questions people ask
How many bundles are in a square?
Usually 3. A square covers 100 sq ft, and most shingles come 3 bundles to the square. Some designer lines are 4 or 5, so read the wrapper.
How many squares are on a 2,000 sq ft house?
It depends on what the 2,000 sq ft is. If it is 2,000 sq ft of roof surface, that is 20 squares, or 22 squares with 10% extra: 66 bundles (69 at 15%). If it is the floor area of a one-story house, the roof is bigger because of the slope and overhang. A 50 × 40 ft house (2,000 sq ft) with 1 ft of overhang is 52 × 42 ft, and at 6/12 that roof is about 2,442 sq ft, which makes 26.9 squares with 10% extra and 81 bundles.
How much waste should I add?
10% for a simple gable roof and 15% when there are hips, valleys or lots of cuts. A very cut-up roof can need more. Spare bundles are handy for repairs later, and an opened bundle is hard to return.
How do I measure a roof from the ground?
Measure the house length and width at the walls, add about 1 ft on each side for the overhang, and multiply the two. Then multiply by the pitch factor for your slope. Example: 42 × 32 ft is 1,344 sq ft; at 6/12 the factor is 1.118, so the roof is about 1,503 sq ft, or 50 bundles with 10% extra. For pitch, put a level and a tape on a rafter in the attic: the rise over 12 in of run.
What is a roofing square?
A square is 100 sq ft of roof, a 10 × 10 ft patch. Roofers price work and shingles by the square. A 1,500 sq ft roof is 15 squares before waste.