Roofing Calculator

Calculate roofing squares, bundles of shingles, and total surface area based on roof pitch.

Roof Specifications

Unit System

Flat Footprint Area (sq ft)

sq ft

Pitch (Rise / 12)

Material Requirements

Ready for a new roof?

Enter the flat dimensions of your house and the roof pitch to estimate total surface area and materials.

Overview

Roofing is measured in 'Squares', where one square equals 100 square feet (9.29 square meters). Because roofs have pitches, the actual surface area is always larger than the flat footprint of the house. Our calculator accounts for this geometry to provide accurate material estimates.

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Pro Tips

Standard shingle bundles cover 1/3 of a square, so you need 3 bundles per square.
Add 10-15% extra for ridges, hips, and valleys where shingles need to be cut.
Check local codes—some areas allow a second layer of shingles to be installed over an existing one, while others require a full tear-off.

Fun Facts

"The world's oldest roofing material is likely clay tile, with some remains in Greece dating back to the 3rd millennium BC."
"Thatch roofs, made of dry vegetation, are remarkably waterproof because the silica in the stems of the plants naturally repels water."
"A roofing 'square' is exactly 10 feet by 10 feet, or 100 square feet."

Formula: Surface Area = Flat Area × sqrt(1 + (Rise/12)²)

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