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Roofing Calculator

Roof area, squares and shingle bundles from the house footprint and pitch.

Footprint length (incl. overhang)ftFootprint width (incl. overhang)ftPitch (rise per 12)/12Waste allowance%

How it's calculated

Roof area = footprint area × the pitch multiplier √(1 + (pitch ÷ 12)²). A roofing square is 100 sq ft. Most architectural shingles come 3 bundles to a square. Add 10% waste for a simple gable roof and 15% or more for hips and valleys.

Example

A 50 × 30 ft footprint at 6/12: 1,500 × 1.118 = 1,677 sq ft, 18.4 squares with 10% waste — 56 bundles.

Waste allowance by roof shape

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