Roof Square Footage Calculator
Roof area is bigger than the house footprint because of pitch. Enter your house length, width, and roof pitch to get the actual surface area, plus shingle bundles needed.
Actual roof area
0
square feet
- Footprint
- 0 sq ft
- Roof "squares"
- 0
- Bundles needed
- 0
- With overage
- 0 sq ft
- Estimated cost
- $0
Why pitch matters
A flat roof's surface area equals its footprint. A pitched roof has a longer slope from eave to ridge, so the actual surface is larger. A standard 6/12 pitch adds about 8% to the footprint. A steep 12/12 pitch adds 41%. Multiplying footprint by the pitch factor gives you the true area you need to cover with shingles, underlayment, and flashing.
Pitch multipliers
| Pitch | Multiplier | Angle |
|---|---|---|
| 2 / 12 | 1.014 | 9.5° |
| 4 / 12 | 1.054 | 18.4° |
| 6 / 12 | 1.118 | 26.6° |
| 8 / 12 | 1.202 | 33.7° |
| 10 / 12 | 1.302 | 39.8° |
| 12 / 12 | 1.414 | 45° |