Roofing Material Calculator

How this calculator works

The footprint is multiplied by the pitch slope factor and waste allowance. Bundle quantity uses a 33.3 sq ft coverage assumption.

Change one assumption at a time to see which inputs have the greatest effect on the estimate.

Worked example

A 40 ft by 30 ft, 6/12 roof with 10% waste has about 1,475.8 sq ft of coverage.

Limitations

This simplified estimate excludes overhangs, hips, valleys, openings, underlayment, and local installation requirements. Confirm manufacturer coverage and a qualified roofer's takeoff.

Review this educational estimate against current quotes, official information, and your own budget before making a financial decision.