Roofing Calculator for a House
Estimate shingle bundles and squares for a full re-roof.
A whole-house re-roof is measured in roofing squares (100 sq ft each) — the industry-standard unit for ordering shingles and underlayment. Most asphalt shingles come 3 bundles per square. Add 10–15% waste for hip and valley cuts and always order one extra bundle for future repairs.
Squares
13.42
1,342 ft²
Shingle bundles
41
3 bundles / square
Underlayment rolls
4
400 ft² rolls
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Recommended tools & materials
Handy picks for this project on Amazon.
Roofing Nailer
Speed up shingle installation
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Synthetic Roof Underlayment
Lightweight, tear-resistant
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Roofing Safety Harness Kit
Stay safe on steep pitches
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Utility Knife with Hook Blades
Cut shingles cleanly
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How does the roofing calculator work?
Roof area = house footprint × pitch factor. The pitch factor is √(1 + (rise/12)²): a 6:12 roof has a 1.118 factor. A "square" is 100 ft² of roof. Shingles are sold in 3 bundles per square.
Which guide explains this in more depth?
- Panel roofs waste differently from shingles: ribs, hips and valleys all change the number you order. Read the metal roofing calculator waste factor guide for the full worked example.
What else do people ask about this calculator?
How many squares of shingles for a 2,000 sq ft house?
A 2,000 sq ft house with a 6:12 pitch has ~2,240 sq ft of roof surface = 22 squares. That's 66 bundles of standard 3-tab or architectural shingles.
How many bundles per square of shingles?
3 bundles per square for architectural (dimensional) shingles, which are the standard today. Older 3-tab shingles sometimes come 4 bundles per square.
How many bundles of shingles do I need?
3 bundles per roofing square. For a 40×30 ft home with a 6:12 roof: about 13.4 squares × 3 = 41 bundles.
What is a roofing square?
100 ft² of roof surface. Shingles are priced per square and packaged in bundles that cover ~33 ft² each.
Which related calculators should I use next?
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