Free Tool

Roof Size Calculator

Enter your home's footprint and roof pitch to estimate total roofing square footage instantly.

Estimated Roof Area
square feet
Roofing squares
With 10% waste
Shingle bundles

Roof Pitch Factor Table

PitchDescriptionMultiply by
1/12 – 2/12Flat / nearly flat1.00 – 1.02
4/12Low slope1.06
6/12Moderate (most common)1.12
8/12Steep1.20
10/12Very steep1.30
12/12Extreme (45°)1.41

Frequently Asked Questions

How do I calculate roof square footage?

Multiply your home's footprint (length × width) by the pitch factor for your roof. Then add 10–15% for waste and overlap. The result is the total roofing area in square feet.

What is a roofing square?

One roofing square equals 100 square feet. Roofing contractors price materials and labor by the square. A typical 2,000 sq ft footprint home with a 6/12 pitch needs about 22–24 squares.

How much does roofing cost per square?

Asphalt shingles typically cost $350–$550 per square installed. Metal roofing runs $700–$1,200 per square. Tile roofing costs $800–$1,500 per square, including materials and labor.

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