Roof Shingle Chart: 3-Tab vs Architectural by Roof Size

How many bundles does a 1,800 sq ft roof need?

54 bundles — 60 to order, 1,620 three-tab shingles, 5,760 nails and 5 rolls of #15 felt. A 1,800 sq ft roof is 18 squares, and at 3 bundles per square that is 54 bundles before waste; 10% waste takes the order to 60. The shingles are 60 bundles × 27 per bundle, the nails are 18 squares × 320, and the felt is 18 squares ÷ 4, rounded up to 5 rolls. That is the whole calculation: area divided by 100 is the squares, squares times 3 is the bundles, bundles times one plus the waste is the order, and the shingles, nails and felt follow from the squares. The table above gives all six numbers for every roof from 1,000 to 3,000 sq ft, for both shingle types, so the same arithmetic works for any roof.

Roof shingle chart — three-tab vs architectural, 10% waste

Both three-tab and standard architectural shingles are 3 bundles per square (33.3 sq ft per bundle) — two independent sources agree: smartroofingcalculator.com ("Three. A roofing square is 100 square feet of finished roof, and a bundle of standard three-tab or architectural shingles covers 33.3 square feet, so three bundles make one square") and owlroofing.com ("Three-tab and standard architectural asphalt shingles come bundled so that 3 bundles = 1 square"), cross-checked against coolconversion.com and topproroof.com, which give the same 3-bundle standard. Only heavy designer and shake-style lines take 4–5 bundles per square. The shingles per bundle are the typical counts — three-tab about 26–27 per bundle, architectural about 22 (smartroofingcalculator.com table; owlroofing.com gives 26–29 and 22–25) — and the wrapper on the bundle you buy governs. Nails are 320 per square (4 nails × 80 shingles per square): the site's own roofing-nail-chart and calculatorzilo.com agree on about 320 per square, rounded up to the nearest hundred. One roll of #15 felt covers 4 squares / 400 sq ft (inchcalculator.com and hunker.com agree); synthetic underlayment covers 10 squares per roll. The table is for 10% waste; the calculator above works out any roof area, shingle type and waste allowance.

Three things to check before you trust the number

Both types are 3 bundles per square — the shingles per bundle are what differ. A bundle of three-tab covers 33.3 sq ft and a bundle of standard architectural covers 33.3 sq ft too, so either type needs 54 bundles for 18 squares. The difference is the piece count: a three-tab bundle holds about 27 shingles and an architectural bundle about 22, because the architectural shingle is bigger and heavier — 1,620 three-tab shingles against 1,320 architectural for the same roof. Only heavy designer and shake-style lines break the rule, at 4–5 bundles per square. If a quote prices architectural by the bundle as if it took more bundles per square, the bundle count is wrong — check the coverage printed on the wrapper, which beats any rule of thumb.

Order the waste figure, not the exact figure. Shingles are cut at every edge, valley, hip and pipe: 10% waste on 54 bundles is 6 extra, taking the order to 60, and 15% takes it to 63. The nails, though, are counted on the installed squares — 5,760 for 18 squares — because the cut-off shingles are never nailed, so their nails are never used. A plain gable roof is fine at 10%; a cut-up roof with hips, valleys and dormers wants 15%. And the roof area is the roof, not the footprint: on a simple roof between 4/12 and 8/12 pitch, the roof is about 5% to 20% bigger than the footprint, so measure the roof planes, not the ground floor.

The felt and the nails are separate orders, and both round up. One roll of #15 felt covers 4 squares, so 18 squares need 5 rolls — 4 rolls cover only 16 squares, 2 squares short — and synthetic underlayment covers 10 squares per roll, so the same roof needs 2 rolls of synthetic. The nails are 320 per square at 4 nails per shingle, 5,760 for 18 squares; high-wind areas use 6 nails per shingle, about 480 per square, which would be 8,640 nails for this roof. A box holds about 7,200 nails, so this roof needs one box at 4 nails a shingle and two at 6. Buy the nails by the box and the felt by the roll, and the shingles by the bundle — three separate counts, all from the same squares.

Worked example

On the defaults: a 1,800 sq ft roof, three-tab shingles, 10% waste.

1. The squares: 1,800 ÷ 100 is 18 squares.
2. The bundles: 18 × 3 is 54 bundles.
3. The waste: 54 × 1.10 is 59.4, rounded up to 60 bundles.
4. The shingles: 60 × 27 is 1,620 shingles.
5. The nails: 18 × 320 is 5,760 nails.
6. The felt: 18 ÷ 4 is 4.5, rounded up to 5 rolls.

And the other way: a 1,000 sq ft roof needs 33 bundles with waste, 10 squares need 3,200 nails, and a 1,800 sq ft roof needs 5 rolls of #15 felt.

Every branch, checked

• 1,000 sq ft roof instead of 1,800: 1,000 sq ft roof instead of 1,800: 1000 sq ft of Three-tab: 10 squares, 30 bundles (33 with 10% waste) — 891 shingles, 3200 nails, 3 rolls of #15 felt.
• 2,500 sq ft roof instead of 1,800: 2,500 sq ft roof instead of 1,800: 2500 sq ft of Three-tab: 25 squares, 75 bundles (83 with 10% waste) — 2241 shingles, 8000 nails, 7 rolls of #15 felt.
• Architectural instead of three-tab: Architectural instead of three-tab: 1800 sq ft of Architectural: 18 squares, 54 bundles (60 with 10% waste) — 1320 shingles, 5760 nails, 5 rolls of #15 felt.
• 0% waste instead of 10%: 0% waste instead of 10%: 1800 sq ft of Three-tab: 18 squares, 54 bundles (54 with 0% waste) — 1458 shingles, 5760 nails, 5 rolls of #15 felt.
• 15% waste instead of 10%: 15% waste instead of 10%: 1800 sq ft of Three-tab: 18 squares, 54 bundles (63 with 15% waste) — 1701 shingles, 5760 nails, 5 rolls of #15 felt.
• 3,000 sq ft roof instead of 1,800: 3,000 sq ft roof instead of 1,800: 3000 sq ft of Three-tab: 30 squares, 90 bundles (99 with 10% waste) — 2673 shingles, 9600 nails, 8 rolls of #15 felt.
• 1,500 sq ft roof instead of 1,800: 1,500 sq ft roof instead of 1,800: 1500 sq ft of Three-tab: 15 squares, 45 bundles (50 with 10% waste) — 1350 shingles, 4800 nails, 4 rolls of #15 felt.
• Architectural, 2,500 sq ft roof: Architectural, 2,500 sq ft roof: 2500 sq ft of Architectural: 25 squares, 75 bundles (83 with 10% waste) — 1826 shingles, 8000 nails, 7 rolls of #15 felt.

The reverses, worked backwards

• Bundles for a 1,000 sq ft roof: 33 bundles — at 33 bundles the figures are 1000 sq ft of Three-tab: 10 squares, 30 bundles (33 with 10% waste) — 891 shingles, 3200 nails, 3 rolls of #15 felt.; at the lower neighbor the figures are 900 sq ft of Three-tab: 9 squares, 27 bundles (30 with 10% waste) — 810 shingles, 2880 nails, 3 rolls of #15 felt.; at the upper neighbor the figures are 1100 sq ft of Three-tab: 11 squares, 33 bundles (37 with 10% waste) — 999 shingles, 3520 nails, 3 rolls of #15 felt. — verdict: STEP.
• Nails for 10 squares of roof: 3,200 nails — at 3,200 nails the figures are 1000 sq ft of Three-tab: 10 squares, 30 bundles (33 with 10% waste) — 891 shingles, 3200 nails, 3 rolls of #15 felt.; at the lower neighbor the figures are 900 sq ft of Three-tab: 9 squares, 27 bundles (30 with 10% waste) — 810 shingles, 2880 nails, 3 rolls of #15 felt.; at the upper neighbor the figures are 1100 sq ft of Three-tab: 11 squares, 33 bundles (37 with 10% waste) — 999 shingles, 3520 nails, 3 rolls of #15 felt. — verdict: STEP.
• Felt rolls for a 1,800 sq ft roof: 5 rolls — at 5 rolls the figures are 5 rolls of #15 felt cover up to 2,000 sq ft (20 squares).; at the lower neighbor the figures are 4 rolls of #15 felt cover up to 1,600 sq ft (16 squares).; at the upper neighbor the figures are 6 rolls of #15 felt cover up to 2,400 sq ft (24 squares). — verdict: STEP.

What the defaults assume

The defaults are a 1,800 sq ft roof of three-tab asphalt shingles with a 10% waste allowance. The roof area is the area of the roof planes, pitch already counted — not the footprint of the house. Both three-tab and standard architectural shingles are 3 bundles per square (33.3 sq ft per bundle), agreed by two independent sources and cross-checked against two more; only heavy designer and shake-style lines take 4–5 bundles per square. The shingles per bundle are the typical counts — three-tab 27, architectural 22 — and the wrapper on the bundle you buy governs. The nails are 320 per square at 4 nails per shingle, the site's own roofing-nail-chart figure, agreed by an independent calculator; high-wind areas use 6 nails per shingle. One roll of #15 felt covers 4 squares (400 sq ft), agreed by two independent sources; synthetic underlayment covers 10 squares per roll. The model does not count starter strip, drip edge, ridge cap, ice and water shield, or flashing — all real materials that sit outside the shingle, nail and felt count — and it assumes a single layer of felt on a roof steeper than 4/12. The bundle and roll counts always round up, because a roof that needs 59.4 bundles needs 60, not 59.

These notes repeat in every explainer section because this page is built to be read start to finish: both types are 3 bundles per square — the shingles per bundle are what differ; order the waste figure, not the exact figure; and the felt and the nails are separate orders, and both round up.

Output · formula · meaning

Who uses this

• A DIYer re-roofing a garage — a 1,000 sq ft roof needs 30 bundles, 33 to order, 891 three-tab shingles, 3,200 nails and 3 felt rolls: the shopping list, before the store trip.
• A roofer pricing a job — a 3,000 sq ft roof needs 90 bundles, 99 with waste, 2,673 three-tab shingles or 2,178 architectural, and 9,600 nails: the order quantity, with both types priced.
• A homeowner comparing three-tab against architectural — the same 1,800 sq ft roof is 1,620 three-tab shingles or 1,320 architectural: the bundles are the same, the piece count is not, and the price per bundle is the decider.
• A student learning roofing rates — one worked example from area to squares to bundles to shingles to nails to felt, the 6-row table, and the reverses that solve for the bundles, the nails and the rolls.

Accuracy & limitations

Figures are the model's own totals on the numbers you type, computed from unrounded values: the squares are the area divided by 100, the bundles are the squares times 3, rounded up, the bundles with waste are the bundles times one plus the waste allowance, rounded up, the shingles are the bundles with waste times the shingles per bundle, the nails are the squares times 320, and the felt rolls are the squares divided by 4, rounded up. The displayed figures are rounded to 2dp where they are not whole. The 3-bundles-per-square rate for three-tab and standard architectural shingles is agreed by two independent sources and cross-checked against two more; heavy designer and shake-style lines take 4–5 bundles per square, so check the coverage printed on the wrapper for the shingle you actually buy. The shingles per bundle (three-tab 27, architectural 22) are typical counts from the published ranges (26–29 and 22–25) — the wrapper governs. The nail figure of 320 per square is 4 nails per shingle on 80 shingles per square, agreed by the site's own roofing-nail-chart and an independent calculator; one source gives about 400 per square, and high-wind areas use 6 nails per shingle (about 480 per square), so treat the nail count as the standard-nailing estimate and check the shingle spec sheet. The felt figure is one #15 roll per 4 squares; low-slope roofs (2/12 to 4/12) need double underlayment. The model assumes the roof area is measured on the roof planes and does not count starter, drip edge, ridge cap, ice and water shield, or flashing. This page is a calculation tool, not a trade guide: follow the shingle manufacturer's directions for nailing and underlayment.

Cite this calculator

A 1,800 sq ft roof of three-tab shingles needs 54 bundles (60 with 10% waste), 1,620 shingles, 5,760 nails and 5 rolls of #15 felt. Rates: 3 bundles per square for three-tab and standard architectural (smartroofingcalculator.com, owlroofing.com); 320 nails per square (roofing-nail-chart); #15 felt 4 squares per roll (inchcalculator.com, hunker.com). Source: Bright Side Kit, brightoolbox.com.

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