Roofing Calculator
Calculate roofing materials, shingles, and costs based on roof dimensions and pitch.
Result
Fill in the fields above, then press Calculate.
A roofing calculator estimates the number of shingle squares and bundles needed based on your building footprint, roof pitch, and waste allowance.
Examples
40x30 ft building with 6/12 pitch
Flat area: 1,200 sq ft. Pitch multiplier: 1.118. Roof area: 1,341.6 sq ft. With 10% waste: 1,475.8 sq ft = 14.76 squares = 45 bundles.
Frequently Asked Questions
What is a roofing square?
A roofing square is a unit of measurement equal to 100 square feet of roof area. It is the standard unit used when ordering roofing materials.
How much waste should I plan for?
A standard gable roof typically needs 10% waste. Hip roofs or complex roofs with many valleys and dormers may need 15-20%. Very simple shed roofs may need only 5%.
Result
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Quick Tips
- •Always round up when ordering materials -- running short is more expensive than having extra.
- •Measure your roof from the ground using the building footprint and pitch multiplier rather than climbing on the roof.
- •Order all shingles from the same production lot to avoid color variation between bundles.