Roofing Shingle Calculator
Example: Total roof area: 2000 sq ft · Waste allowance: 12 % · Bundles per square: 3 bundles · Price per bundle: 38 $
| Roofing squares | 22.4 |
| Bundles to buy | 68 |
| Total shingle cost | $2,584 |
Worked example
A 2,000 square foot roof with a 12% waste allowance becomes 2,240 square feet, which is 22.4 squares. With three-tab-style shingles at 3 bundles per square, that is 22.4 x 3 = about 68 bundles. At $38 a bundle the shingles run roughly $2,584. The waste allowance matters here because hips, valleys, and starter and ridge rows all consume shingles that never lie flat on the main field.
Frequently asked questions
What is a roofing square?
A square is 100 square feet of roof surface, the standard unit roofers use for estimating and pricing. Dividing your total roof area by 100 gives the number of squares, which is what a supplier and a labor quote will reference.
How much waste should I allow for shingles?
A simple gable roof needs around 10%, while a complex roof with many hips, valleys, and dormers can need 15% or more because of all the angled cuts. Ridge caps and starter strips also consume shingles beyond the plain field area.
Does this include the roof pitch?
You should enter the actual sloped roof area, not the building footprint, because a steep roof has much more surface than the floor beneath it. If you only know the footprint, multiply by a pitch factor first, then enter that larger area here.
How many bundles make a square?
Most architectural and three-tab asphalt shingles are packaged three bundles to the square, though some heavy or premium products use four. Check your shingle's wrapper and set the bundles-per-square input to match before ordering.