Roof planning
How Many Bundles of Shingles in a Square and Per Roof?
One roofing square is 100 square feet and takes 3 bundles of standard asphalt shingles. Find roof area by multiplying the house footprint by a pitch factor, add 10 to 15 percent for waste, divide by 100, and multiply by 3.
Open the roof shingle calculatorSquares and bundles
Roofers measure in squares. One square covers 100 square feet of roof. Standard three-tab and most architectural shingles are packaged three bundles to the square, so each bundle covers about 33.3 square feet. Some heavy designer shingles take four or five bundles per square, and the wrapper states the coverage.
| Shingle type | Bundles per square | Shingles per bundle |
|---|---|---|
| 3-tab (12 x 36 in, 5 in exposure) | 3 | About 26 |
| Architectural or laminated | 3, some brands 4 | About 22 |
| Designer or luxury | 4 to 5 | Varies, see the wrapper |
| Hip and ridge cap | Sold by linear feet | About 20 to 33 linear ft per bundle |
| Starter strip | Sold by linear feet | About 100 to 120 linear ft per bundle |
Bundles needed by roof size
Roof area is the sloped surface, not the floor area of the house. A 2,000 square foot two-story house may have a footprint near 1,000 square feet, and its roof area is that footprint times the pitch factor below, plus overhangs.
| Roof area | Squares | No waste | 10% waste | 15% waste |
|---|---|---|---|---|
| 1,000 sq ft | 10 | 30 bundles | 33 bundles | 35 bundles |
| 1,200 sq ft | 12 | 36 bundles | 40 bundles | 42 bundles |
| 1,500 sq ft | 15 | 45 bundles | 50 bundles | 52 bundles |
| 2,000 sq ft | 20 | 60 bundles | 66 bundles | 69 bundles |
| 2,500 sq ft | 25 | 75 bundles | 83 bundles | 87 bundles |
| 3,000 sq ft | 30 | 90 bundles | 99 bundles | 104 bundles |
From footprint to roof area
You can estimate roof area safely from the ground. Measure the length and width of the house including overhangs, multiply them for the footprint, and multiply by the pitch factor for your roof slope.
| Roof pitch | Pitch factor | Roof area for a 1,500 sq ft footprint |
|---|---|---|
| 3/12 | 1.031 | 1,547 sq ft |
| 4/12 | 1.054 | 1,581 sq ft |
| 5/12 | 1.083 | 1,625 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 |
A worked example
A 40 x 28 foot footprint is 1,120 square feet. At a 6/12 pitch, 1,120 x 1.118 = 1,252 square feet of roof. Add 15 percent waste for 1,440 square feet, or 14.4 squares. At 3 bundles per square that is 43.2, so order 44 bundles.
Waste and the rest of the order
Use about 10 percent waste for a simple gable roof and 15 percent or more for hip roofs, valleys, and dormers. Starter strips and ridge caps are separate products measured in linear feet.
- Underlayment: synthetic rolls commonly cover about 10 squares, and a roll of 15 lb felt covers about 4.
- Nails: about 320 per square at four nails per shingle, and about 480 in high-wind areas that require six.
- Drip edge: measure all eaves and rakes in linear feet.
- Ridge caps and starter strip: measure ridges, hips, and eaves in linear feet.
- Flashing, pipe boots, and vents as needed.
Stay off the roof
This estimate is for understanding a quote or budgeting, and the footprint method keeps you on the ground. Roof work involves serious fall risk. Leave on-roof measuring and installation to people with fall protection and training.
- One square is 100 square feet and takes 3 bundles of standard shingles.
- Roof area = footprint x pitch factor. A 6/12 roof is 1.118.
- Add 10 percent waste for gable roofs and 15 percent or more for complex roofs.
Run the numbers
The Roof Shingle Calculator applies this math to your own measurements and shows each step. Best for rough planning and quote checking, not for walking or measuring a roof.