How the calculation works

Roof area = footprint × √(1 + (rise/12)²). Bundles = area × waste ÷ 33.3.

Example

A 40×24-foot gable footprint at 6:12 pitch with 10% waste needs about 36 bundles.

When to use this calculator

Use it for early material planning; add separate allowances for complex valleys and hips.

Results are planning estimates. Verify critical dimensions, machine settings, material specifications, and local code requirements before work begins.