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Roof shingle calculator
ARMA
Result
Squares
Bundles
Region
Waste
Prices: national avg · Jun 2026 · sources
DiagramUpdates as you type

Estimate shingle bundles from your roof area in squares, with a waste factor for cuts and starter courses.

Formula

bundles = squares × bundles_per_square × (1 + waste)

Method & sources
Formula basisARMA
How we calculateRoof area ÷ 100 = squares; 3 bundles per square (architectural), plus a waste allowance. Full method →
Formula verified against the published standard above. Method last reviewed June 2026. Estimates are for planning — confirm against supplier quotes.

How it works

Three bundles of standard 3-tab shingles cover one square (100 ft²). Use the roofing calculator to get your square count from the footprint and pitch.

Starter and ridge

Add extra bundles for starter strips and ridge caps, which the waste factor partly covers.

Worked example

Shingles for a 25-square roof

If the roofing calculator told you the roof is 25 squares, standard 3-tab shingles at 3 bundles per square need 75 bundles before waste. With 10% waste that's about 83 bundles.

Architectural (dimensional) shingles sometimes run a bit heavier per square — check the wrapper, as some need 4 bundles per square. Also budget separately for hip and ridge caps and starter strip, which are sold as specialty bundles.

What affects your result

Common mistakes to avoid

Where the numbers come from

Three bundles per square is standard for 3-tab; architectural shingles vary by product. Get squares from the roofing calculator.

Bundles per square

Most architectural shingles come three bundles to a square (100 sq ft); heavier designer shingles may be four or five bundles per square. Convert your sloped roof area to squares, add waste, and multiply by the bundles-per-square for your product. Always confirm the coverage on the wrapper, since it varies by shingle line.

Waste, starter, and ridge cap

Add about 10% waste for a simple gable roof and 15% for a cut-up roof with many hips and valleys, where every cut produces an offcut. Starter shingles along the eaves and ridge-cap shingles along the ridges and hips are separate from the field bundles — measure those edges in linear feet and convert to bundles per the product's coverage.

Frequently asked questions

How many bundles of shingles per square?

Three for standard 3-tab shingles; some architectural shingles need four.

How many bundles of shingles per square?

Most architectural shingles are three bundles per square (100 sq ft), while heavier designer shingles can be four or five. Check the wrapper, since coverage varies by product line.

How much waste should I add for shingles?

About 10% for a simple gable roof, rising to 15% for complex roofs with many hips and valleys where each cut creates an offcut.

Do I count starter and ridge-cap shingles separately?

Yes. Starter shingles at the eaves and ridge-cap shingles along ridges and hips are measured in linear feet and ordered separately from the field bundles.

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