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Roofing Calculator

Calculate roofing materials needed including squares, shingle bundles, and underlayment rolls. Supports various roof pitches and shingle types for accurate material estimates.

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How to use Roofing Calculator

  1. Enter roof length and width (the building footprint dimensions).
  2. Select your roof pitch from flat (0/12) to steep (12/12).
  3. Choose shingle type and waste factor, then click Calculate for full material estimates.

What is Roofing Calculator?

A roofing calculator helps estimate the materials needed for a roofing project. Roof area is not the same as the building footprint because the pitch (slope) increases the actual surface area. A steep roof has significantly more surface area than a flat one.

This calculator converts your building footprint to actual roof area using the pitch multiplier, then calculates the number of squares (100 sq ft each), shingle bundles, and underlayment rolls needed.

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FAQ

What is a roofing square?
A roofing square is 100 square feet of roof area. Roofing materials are sold by the square, not by individual square feet.
How many bundles of shingles per square?
Standard 3-tab and architectural shingles come 3 bundles per square. Premium/designer shingles may require 4-5 bundles per square.
How does roof pitch affect material needs?
A 4/12 pitch adds about 6% more area than the footprint. A 8/12 pitch adds about 20%. Steeper roofs need more materials.
What waste factor should I use for roofing?
Use 10-15% for simple gable roofs. Complex roofs with hips, valleys, and dormers may need 15-20% waste factor.

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