Shingles Calculator — bundles and shingle count

How it works

Shingles are sold in bundles, and roofers size a job in squares — one roofing square covers 100 ft² of roof. Convert the roof area to squares, add a waste allowance, then multiply by the bundles it takes to fill a square:

bundles = ⌈area × (1 + waste) ÷ 100 × bundles-per-square⌉

Standard three-tab and architectural asphalt shingles take about 3 bundles per square, but heavier or specialty shingles differ, so the bundles-per-square is an input. Because you buy whole bundles, the result rounds up. The individual shingle count follows from the bundles:

shingles = bundles × shingles-per-bundle

A bundle of asphalt shingles typically holds about 26 shingles for a standard three-tab, though it ranges roughly 21–29 by product — heavier architectural shingles come fewer to a bundle — so that too is an input. Measure the actual roof area along the slope, not the ground footprint — a pitched roof has more surface than the house below it.

Worked example

A 2000 ft² roof with 10% waste is 2000 × 1.1 ÷ 100 = 22 squares. At 3 bundles per square that is ⌈66⌉ = 66 bundles, or 66 × 26 = 1,716 shingles. A small 200 ft² shed needs 7 bundles, and a cut-up 3000 ft² roof at 15% waste takes 104 bundles.

Frequently asked questions

How many bundles of shingles do I need?

Convert roof area to squares (÷ 100), add waste, and multiply by the bundles per square, rounding up: bundles = ⌈area × (1 + waste) ÷ 100 × bundles-per-square⌉. A 2000 ft² roof at 10% waste and 3 bundles per square needs 66 bundles.

How many shingles are in a bundle?

About 26 for a standard three-tab asphalt bundle, and often fewer — roughly 21 to 26 — for heavier architectural shingles. It ranges by product, so it is an input here — check the wrapper for your exact shingle. Three bundles usually make up one 100 ft² square.

What is a roofing square?

A roofing square is 100 square feet of roof surface — a 10 × 10 ft area. Roofers and suppliers quote materials in squares, so converting your roof's area to squares makes ordering shingles, underlayment and other materials straightforward.

How much waste should I add for shingles?

About 10% is typical for a simple gable roof. Complex roofs with many hips, valleys and dormers waste more shingles in cuts, so allow 15% or more. The waste allowance is added before rounding up to whole bundles.

Do I use the roof area or the house footprint?

Use the actual roof area measured along the slope. A pitched roof has more surface than the flat footprint of the house beneath it — the steeper the pitch, the bigger the difference — so measuring the ground area alone undercounts the shingles you need.

What is the difference between this and a roofing calculator?

A roofing calculator reports the job in squares and total bundles for planning and ordering. This shingle calculator adds the individual shingle count — bundles multiplied by the shingles per bundle — which is handy for spot repairs or checking a small order. Both use the same squares-and-bundles arithmetic.