Roofing Calculator

Calculate roofing materials including shingles, underlayment, and ridge caps for your roof.

Part of:Roofing hub
ft
ft
:12
%

How to Use This Calculator

How to Use

  1. Enter the roof footprint length and width (ground-level measurements).
  2. Enter the roof pitch (rise per 12 inches of run).
  3. Adjust waste percentage (15% is typical for roofing).

Tips

  • The calculator adjusts flat area to sloped area using the pitch multiplier.
  • A “roofing square” equals 100 sq ft (9.29 m²).
  • Standard 3-tab shingles: 3 bundles per square. Architectural shingles may vary.

Common Questions

How many bundles of shingles do I need?

Most shingles come 3 bundles per square (100 sq ft). Calculate your roof area in squares and multiply by 3.

What is a roofing square?

A roofing square is 100 square feet (9.29 m²). It’s the standard unit for measuring and ordering roofing materials.

How does pitch affect material quantity?

Steeper pitches have more surface area. A 6:12 pitch adds about 12% more area than a flat roof; a 12:12 pitch adds about 41%.

How long does a roof last?

Asphalt shingles typically last 20–30 years, concrete tiles 40 years or more, and natural slate far longer. Lifespan depends on the material, the pitch and how exposed the roof is.

How do I measure roof area without climbing up?

Work out the footprint from the ground and multiply by a pitch factor for the slope. Our Roof Area calculator does exactly this from your plan size and pitch.

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