What a roofing square is
Roofers price and order by the square. One square covers 100 square feet of roof. A roof of 2,400 square feet is 24 squares. Bids, shingle wrappers and material orders all use squares, so it helps to know your number before you compare quotes.
Start with the footprint: the outside of the walls, plus the overhang at the eaves and the gable ends. A plan of the house or a satellite map gives you the length and width. The roof slopes, so it has more area than the footprint. The pitch multiplier adds that extra. Not sure of your pitch? Use our roof pitch calculator.
Example: a 2,000 square foot footprint
The same house at five pitches. A steeper roof needs more squares and more bundles.
| Pitch | Multiplier | Roof area | Squares | Bundles | With 10% waste |
|---|---|---|---|---|---|
| 4:12 | 1.054 | 2,108 sq ft | 21.1 | 64 | 70 |
| 6:12 | 1.118 | 2,236 sq ft | 22.4 | 68 | 74 |
| 8:12 | 1.202 | 2,404 sq ft | 24.0 | 73 | 80 |
| 10:12 | 1.302 | 2,604 sq ft | 26.0 | 79 | 86 |
| 12:12 | 1.414 | 2,828 sq ft | 28.3 | 85 | 94 |
How we calculate
Roof area is the footprint times the pitch multiplier. Squares are the roof area divided by 100. Bundles are the squares times 3, rounded up, since most asphalt shingles come 3 bundles to a square. The bundle count for each square is printed on the wrapper, and heavier shingles need more bundles per square. The waste line adds 10% for cuts at hips, valleys and edges, and for the starter rows. A roof with many hips and valleys can need more.
This is a first number for one simple roof shape. A roofer measures every plane, dormer and porch roof before a bid. To turn your squares into a price, use our roof cost calculator.