How it works
Use the result as a checked starting point.
Roof footprint is not roof surface area once pitch is introduced. This calculator applies a pitch factor, adds waste, and estimates three-tab or architectural shingles at three bundles per square.
Complex roofs need field measurement or plan takeoff by section. Valleys, dormers, hips, starter, ridge, flashing, ventilation, tear-off, disposal, access, and deck repair belong in a complete bid.
Roof area = footprint × pitch factor. Roofing squares = area with waste ÷ 100.
Estimating checks
- Break irregular roofs into measurable sections.
- Increase waste for hips, valleys, and cut-up layouts.
- Confirm bundle coverage for the exact shingle product.
Common questions
What is a roofing square?
One roofing square equals 100 square feet of roof surface.
Are there always three bundles per square?
Many common shingles use three, but some products differ. Verify package coverage.
Does pitch factor replace measuring the roof?
No. It is a planning conversion from footprint and should be checked against plans or field dimensions.