Roofing Shingle Calculator
Squares and bundles of shingles from footprint and pitch.
Measure at the eaves, including overhangs.
10% for simple gable roofs, 15% for roofs with hips, valleys, or dormers.
You need
45 bundles
Assumes 3 bundles per square, standard for architectural shingles.
- Roof area (with waste)
- 1,476 sq ft
- Roofing squares
- 14.8 squares
- Synthetic underlayment
- 2 rolls
Estimates only. Verify quantities before ordering.
How this is calculated
Roof area = footprint x pitch multiplier x (1 + waste), where the multiplier is sqrt(1 + (rise/12)^2). Squares = area / 100. Bundles = squares x 3, rounded up, since standard architectural shingles pack three bundles per square. Underlayment assumes a 10-square synthetic roll.
Roofers measure in squares, where one square is 100 square feet of roof surface. This calculator starts from your home's footprint (the area the building covers on the ground, including eave overhangs), scales it up by a pitch multiplier to account for the slope, adds waste, and converts the result into squares, shingle bundles, and underlayment rolls.
Pitch is written as rise over run: a 6/12 roof rises 6 inches for every 12 inches of horizontal distance. You can measure it from inside the attic with a level and a tape measure. The steeper the pitch, the more actual roof surface sits above the same footprint, which is exactly what the multiplier captures.
Shingles for common roof sizes
Rows assume a 6/12 pitch and 10% waste, with the footprint measured at the eaves. Steeper roofs need more; use the calculator above to adjust pitch.
| Footprint | Bundles | Squares |
|---|---|---|
| 24 x 30 ft (720 sq ft) | 27 bundles | 8.9 squares |
| 26 x 40 ft (1,040 sq ft) | 39 bundles | 12.8 squares |
| 30 x 40 ft (1,200 sq ft) | 45 bundles | 14.8 squares |
| 28 x 48 ft (1,344 sq ft) | 50 bundles | 16.5 squares |
| 40 x 50 ft (2,000 sq ft) | 74 bundles | 24.6 squares |
Common questions
What is a square in roofing?
One square equals 100 square feet of roof surface. Shingles, underlayment, and roofing labor are all priced per square, so a 24 square roof means 2,400 square feet of surface to cover, regardless of the shape of the roof.
How many bundles of shingles are in a square?
Standard architectural (dimensional) shingles are packaged three bundles per square. Some heavyweight designer shingles run four or even five bundles per square, so check the wrapper before converting. Three-tab shingles are also three bundles per square.
How do I measure my roof pitch?
In the attic, hold a level horizontally against a rafter, measure 12 inches along the level from where it touches, then measure straight down from the level to the rafter. That vertical distance in inches is your pitch: 6 inches means a 6/12 roof. From outside, a pitch gauge app against the gable edge also works.
How much waste should I add for a roof?
Use 10% for a simple gable roof with two rectangular planes. Roofs with hips, valleys, dormers, or multiple sections cut a lot more shingles, so use 15%. Complex roofs can justify 20%, and valleys also consume extra underlayment and flashing beyond the shingles themselves.