How this roofing shingle calculator works
Roof area is increased by the waste allowance. The calculator divides by 100 for roofing squares and by your bundle coverage for whole bundles.
How to use it
- Total roof surface area. Enter the value in sq ft.
- Waste allowance. Enter the value in %.
- Coverage per bundle. Enter the value in sq ft.
- Request the result. Add your email, then select “Email & show my result.”
What to do with the number
Complex valleys, hips and cut-up roof geometry usually need a larger waste allowance than a simple gable roof. Use measured roof surface area, not the home’s floor area, because roof slope increases surface area.
Planning estimate
Use this result as a starting point, not a guarantee. Product specifications, site conditions, manufacturer guidance, local codes, taxes, labor, tolerances, and rounding can change the real requirement or cost.