Shingle Calculator

Convert net roof area into roofing squares and field-shingle bundles with an editable waste allowance and bundle coverage.

Calculate

This tool takes the net measured roof area, applies a waste allowance to get the order area, then divides by the coverage printed on a bundle and rounds up. Order area, squares and bundles are shown as separate numbers so you always see the measured roof and the purchase quantity side by side.

Net area to order quantity

The sequence is: net area → waste-adjusted order area → coverage per bundle → bundles rounded up. One roofing square is 100 sq ft. Many three-tab style shingles cover about 33⅓ sq ft per bundle, so three bundles make a square, but architectural and specialty shingles differ. Always use the coverage on the package you are buying rather than a universal rule.

Field shingles vs. cap and starter

Field shingles cover the open roof planes. Hip-and-ridge cap and starter strip are separate products with their own coverage and allowances, so they are not part of this field-bundle count. Estimate cap in the ridge cap calculator where it belongs, and read the waste guide for how much to add.

Why a universal three-bundle rule can fail

The "three bundles per square" shortcut only holds for products that actually cover 33⅓ sq ft per bundle at the stated exposure. Heavier shingles cover less, so the same square can need four or more bundles. Rounding also matters: round after computing the order area, not before, so you do not quietly lose or add a bundle.

If you enter a price per bundle the calculator can show a materials-only subtotal from your own figure. It does not invent nationwide installed costs, which depend on labor, tear-off and your local market.