Roofing calculator
Enter the building footprint and the pitch. Jobmath gives the roof area, squares and bundles.
How it's calculated
Each step, in the order Jobmath runs it.
| Step | Formula |
|---|---|
| Pitch factor | √(1 + (rise ÷ 12)²) |
| Roof area | Length × width × pitch factor |
| Squares | Roof area × (1 + waste %) ÷ 100 |
| Bundles | Squares × bundles per square, rounded up |
Pitch factors
Multiply the footprint by the factor to get the roof area.
| Pitch | Factor | Angle |
|---|---|---|
| 3/12 | 1.031 | 14.0° |
| 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 | 45.0° |