Shingle calculator

This shingle calculator turns roof area into bundles. Pam's 1,625 sq ft roof with 10% waste needs about 54 bundles, or 17.9 squares.

Your area

Use the roof surface, not the floor of the house. If you only know the footprint, run it through the roof size calculator first.

Bundles per square

Standard shingles come three bundles to a square of 100 sq ft. Omni Calculator says a bundle typically covers 33.3 sq ft. Some heavy designer shingles pack four or five bundles to a square, so read the wrapper.

The bundle figure is from the Omni shingle calculator.

Waste

A plain gable wastes about 10%, per BuildFolio. Hips and valleys push it to 15% or 20%. Starter strips and ridge caps are extra and sold by the linear foot.

That 10% starting point comes from BuildFolio.

Cost by shingle grade

Installed asphalt runs $3.44 to $12 per sq ft, per This Old House. Homewyse's September 2026 national figure is narrower at $5.21 to $6.82. Three-tab sits at the low end and architectural above it.

Grade also sets life span. Owens Corning gives 20 years for three-tab and 30 years for architectural shingles. Prices are from This Old House and Homewyse; life spans from Owens Corning.

How the shingle calculator works

Area divided by 100 gives squares. Squares plus waste, times three, gives bundles, rounded up. Round up again for a spare bundle to match future repairs.

Worked examples

1. Pam: 1,625 sq ft, 10% waste, 17.9 squares, 54 bundles.
2. A 2,000 sq ft hip roof with 15% waste: 23 squares, 69 bundles.
3. A 1,200 sq ft garage with 10% waste: 13.2 squares, 40 bundles.