MihsabaHow to use
Calculate roof area including waste and whole shingle bundles using actual roof area and bundle coverage.
- Enter Actual roof area (m²).
- Enter Coverage per bundle (m²).
- Enter Waste (%).
- Calculate, then review the assumptions before purchasing.
How it is calculated
Example
An actual roof area of 160 m² with 10% waste and 3 m² per bundle requires 59 bundles.
Important notes
Use actual sloped roof surface area rather than horizontal footprint unless pitch has already been converted. Valleys, hips and details can increase waste on complex roofs.
Worked examples and interpreting results
An actual roof area of 160 m² with 10% waste and 3 m² per bundle requires 59 bundles.
| Case | Calculation | Result |
|---|---|---|
| Adjusted area | 160 × 1.10 | 176 m² |
| Bundles | ceil(176 ÷ 3) | 59 |
How to check the result
Use actual sloped roof surface area rather than horizontal footprint unless pitch has already been converted. Valleys, hips and details can increase waste on complex roofs.
Frequently asked questions
Can I enter the building footprint?
Prefer actual roof surface area after accounting for pitch; horizontal footprint alone underestimates sloped roofs.
Should I include waste?
Include an allowance when cuts, breakage or layout losses are expected. Use a percentage that fits your project rather than assuming one fixed rate.
Do the units need to match?
Yes. The calculator assumes the units stated beside each field, so convert measurements first when your source uses different units.