Roof Shingle Calculator

Replacing or installing a roof requires knowing exactly how many shingle bundles to buy — too few means a trip back to the store, too many wastes money. Enter your roof length, roof width, roof pitch, shingle coverage per bundle, and a waste factor into the Roof Shingle Calculator to get the total bundles needed. Secondary outputs include total roof area (sq ft), roofing squares, and an optional total material cost if you enter a price per bundle.

ft

Measure the length of your roof at the base

ft

Measure the width of your roof at the base

Rise over run ratio (e.g., 4/12 means 4 inches rise per 12 inches run)

sq ft

Typical asphalt shingles cover 33.3 sq ft per bundle

%

Add extra material for cuts, mistakes, and future repairs

Enter to calculate total material cost

Results

Bundles Needed

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Total Roof Area

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Roofing Squares

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Total Material Cost

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Frequently Asked Questions

What is a roofing square?

A roofing square is a standard unit of measurement in the roofing industry that equals 100 square feet of roof area. It's commonly used to estimate materials and labor costs.

How many shingles are in a bundle?

A standard bundle of asphalt shingles typically contains 20-29 individual shingles, depending on the size and type. Most bundles cover approximately 33.3 square feet of roof area.

How do I measure my roof for shingles?

Measure the length and width of each roof section at the base (footprint), then multiply by the pitch multiplier to account for the slope. For complex roofs, break it into simple rectangular sections and add them together.

Why do I need a waste factor?

The waste factor accounts for cuts around vents and edges, installation mistakes, damaged shingles, and future repairs. A 10-15% waste factor is typical for most roofing projects.

How does roof pitch affect shingle calculations?

Steeper roof pitches increase the actual surface area compared to the footprint area. The pitch multiplier adjusts for this difference to ensure you order enough materials.

What's the difference between a bundle and a square of shingles?

A bundle is the physical packaging unit (usually covers 33.3 sq ft), while a square is 100 sq ft of coverage. You typically need 3 bundles to make one roofing square.

Should I buy extra shingles?

Yes, always buy 10-15% extra shingles beyond your calculated needs. This accounts for waste, future repairs, and ensures you have matching shingles from the same production lot if repairs are needed later.

Can I use this calculator for all shingle types?

This calculator works for most standard asphalt shingles. For specialty shingles like slate, wood, or architectural shingles, check the manufacturer's coverage specifications as they may differ from the standard 33.3 sq ft per bundle.