From footprint to roofing squares
A roofing square is 100 square feet of roof surface. Because a sloped roof is longer than the ground it covers, multiply the footprint by the pitch multiplier:
Roof area = (length + 2 × overhang) × (width + 2 × overhang) × pitch multiplier
Squares = roof area × (1 + waste) ÷ 100
For a 40 × 30 ft house with 12-inch overhangs and a 6/12 roof: 42 × 32 = 1,344 sq ft, times 1.118 = 1,503 sq ft of roof. With 10% waste you order 16.5 squares.
This works for gable and hip roofs of the same pitch, because the multiplier applies to every plane equally. For mixed pitches or dormers, measure each section separately and add them.
How much waste to allow
| Roof type | Typical waste |
|---|---|
| Simple gable | 5 to 10% |
| Hip roof | 10 to 15% |
| Valleys, dormers, skylights | 15 to 20% |
Next, turn squares into bundles with the shingle calculator.
How many squares is my roof?
Multiply the footprint including overhangs by the pitch multiplier, then divide by 100. A 40 × 30 ft house with 1 ft overhangs and a 6/12 roof has about 1,503 sq ft of roof: 15 squares before waste, or 16.5 with 10% waste.
Frequently asked questions
How many square feet is a roofing square?
100 square feet of roof surface.
How many squares is a 2,000 sq ft house?
Usually 22 to 30 squares, depending on pitch, overhang and roof shape. A one-story 2,000 sq ft house with a 6/12 roof and 1 ft overhangs is about 24 squares plus waste.
Does a hip roof have more area than a gable?
At the same pitch and footprint, the area is the same. Hip roofs need more waste and more ridge cap because of the extra cuts.