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About Roofing Calculator

The Roofing Calculator helps homeowners and contractors estimate materials for re-roofing. In the roofing industry, the standard unit of measurement is the "Square".

What is a Square?

1 Square = 100 Square Feet of roof area.
Standard shingle bundles usually cover 33.3 sq ft (3 bundles per square).

Pitch Factor

A roof isn't flat. The steeper the roof, the more surface area it has compared to the footprint of the house. This calculator estimates the simple area (Length x Width) but allows you to add a percentage for pitch/slope and waste.

How to Use

Enter the roof dimensions (or house footprint + overhangs). The tool calculates total square footage, the number of "Squares", and estimated bundles of shingles.