Shingle Bundle Calculator

Shingles are the obvious cost on a roofing order and rarely the whole of it. Starter strip, hip and ridge cap, underlayment, drip edge, ice barrier and nails all get counted separately, and they are where a quantity list usually goes wrong. This turns a roof area into the full list.

Shingle and accessory quantities

Work out bundles, starter strip, hip and ridge cap, underlayment, drip edge and nails from your roof area.

This calculator needs JavaScript to work. The measurements below are the ones you would need to do the sum by hand.

Both come out of the roof area calculator. Use the figure before waste; waste is added below.

Around 10% on a simple gable, 15% or more where there are hips and valleys to cut into.

Printed on the wrapper. Three is the usual answer.

The horizontal bottom edges, where the gutters run.

The sloping edges at the gable ends.

Hips take the same capping as the ridge, so they are counted with it.

Product coverage

Defaults that suit common products. Change them to whatever your own bundles and rolls say they cover.

Ten squares is a standard synthetic roll. Felt is usually four.

Four is standard. High-wind zones and steep pitches call for six.

Bundles of field shingles — Rounded up, waste included. Cap and starter are counted separately below.

Squares including waste
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Starter strip Eaves plus rakes.
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Starter strip needed
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Hip and ridge cap Ridge plus hips.
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Cap needed
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Underlayment
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Drip edge Eaves plus rakes, in whole lengths.
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Ice and water barrier Eaves plus valleys, one course. Cold climates need more at the eaves.
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Roofing nails Assumes about 80 shingles to a square.
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Nails by weight At roughly 140 nails to the pound for 1¼ inch roofing nails.
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Counts are rounded up to whole bundles, rolls and pieces, and the coverage figures they use are the defaults in the product coverage panel. Check them against the wrappers of whatever you are actually buying, because they vary by manufacturer and by product line. Ice and water barrier is quoted as a single course along the eaves and up the valleys; where ice dams are a routine problem, code often requires it to extend past the inside face of the exterior wall, which can mean two or three courses.

Start with the area, then add waste

Use the figure from the roof area calculator before waste, because waste is applied here. Around 10 per cent suits a simple gable roof. Fifteen per cent or more is normal once there are hips and valleys, since every course running into them is cut on the angle and the offcuts are not reusable.

What a bundle covers

Most three-tab and architectural shingles come three bundles to the square, so one bundle covers about 33 square feet. Heavier architectural lines run four to the square and designer products five. The number is printed on the wrapper, and it is the first thing to check before trusting any quantity, including this one.

Bundles are also how weight is managed. Three to the square keeps each bundle around 70 to 80 pounds, which is what one person can carry up a ladder. That is why the heavier products come in more, smaller bundles rather than fewer large ones.

The parts people forget

  • Starter strip runs along the eaves and up the rakes. It is what the first course seals to, and reversing a field shingle to make your own leaves the adhesive strip in the wrong place. Sold by the linear foot.
  • Hip and ridge cap covers the ridge and every hip. Cap is a separate product from field shingles on most architectural lines, and a bundle of it covers far less length than people expect, often around 20 linear feet.
  • Underlayment goes over the whole deck. A standard synthetic roll covers ten squares; felt is usually four, so the same roof needs more than twice as many rolls.
  • Drip edge goes along the eaves and the rakes, in fixed lengths, usually ten feet.
  • Ice and water barrier is a self-adhering membrane at the eaves and up the valleys. The calculator quotes a single course. In a cold climate, code often requires it to reach past the inside face of the exterior wall, which can mean two or three courses at the eaves.

Nails

Four nails per shingle is the standard pattern, which works out at roughly 320 nails per square. High-wind zones and steep pitches call for six, and that is a manufacturer requirement rather than a preference: fastening to a lower schedule than the instructions specify will void the wind warranty. The calculator gives both a count and an approximate weight, since roofing nails are sold by the pound.

Temperature decides when, not how much

Asphalt shingles do not fasten themselves down. Each one carries a strip of sealant that softens in the sun and bonds to the course below, and until that happens the roof is held on by nails alone and is vulnerable to wind. The sealing needs warmth: roughly 40 to 50 °F and some direct sun, depending on the product.

Install below that and the strips will not bond until spring. Manufacturers allow cold-weather work, but they require the shingles to be hand-sealed with dabs of roofing cement in the meantime, and they say so in the installation instructions rather than in the brochure. A winter re-roof done without hand-sealing is a warranty problem waiting for the first gale.

None of this changes the quantities above. It changes the schedule, and it is worth asking any contractor quoting winter work how they intend to handle sealing, and getting the answer in writing.

Check the wrapper, then order

Every coverage figure in the panel marked “Product coverage” is a default that suits common products, and every one of them varies by manufacturer and by line. Open the panel and put in what your own bundles and rolls actually say. A quantity list built on the wrong coverage figure is wrong in a way that only shows up on the roof, on the day, with a crew waiting.

Order through the supplier your contractor uses if there is one. They will price by the square, know what the local code requires at the eaves, and take back unopened bundles, which is worth more than shaving the waste allowance.