Understanding your result
The headline is the number of nails to buy, including the extra for starter, caps and drip edge. The stats repeat the nails per shingle, the weight and the number of boxes. The breakdown shows the shingles nailed, the field nails, the extras and how the count becomes pounds and boxes.
The number to carry to the store is the boxes, but the number to check is the field nail count against the shingle count: at four per shingle, the nails are simply four times the shingles the shingle calculator gave you. If the two disagree, one of them has a different squares figure or shingle type.
The weight is there for two reasons: hand nails are sold by the pound, and a roof’s worth of nails is heavier than people expect. Thirty pounds of nails for a modest roof is normal.
How we calculate this
The non-obvious input is the shingles per square. Three-tab shingles are 12 by 36 inches and packed about 26 to a bundle, so a square has about 80. Architectural shingles are the same width but 13¼ inches or so tall with a longer exposure, packed about 21 to a bundle, so a square has about 64. Fewer shingles means fewer nails for the same roof, which is why the shingle type is a field here. The shingle coverage table gives the counts per bundle for the common products.
Nails per pound fall as nails get longer because each one is heavier. The defaults are approximate figures for 11-gauge galvanized roofing nails; the box prints the exact count, and that is the one to use.
The assumptions behind the numbers
| Assumption | Default | Where it comes from |
|---|---|---|
| Nails per shingle | 4, or 6 in high wind | ARMA and manufacturers’ installation instructions; IRC R905.2.6 requires a minimum of 4 per strip shingle |
| Shingles per square | 64 architectural, 80 three-tab | Manufacturers’ bundle counts (about 21 and 26 per bundle at 3 bundles per square) |
| Nails per pound by length | 250 / 200 / 165 / 145 / 125 for 1 / 1¼ / 1½ / 1¾ / 2 in | Approximate counts for 11-gauge galvanized roofing nails from fastener makers’ charts; the box states the exact figure |
| Coil nail box | 7,200 nails | Common packaging for 1¼-in coil roofing nails (60 coils of 120) |
| Extra for starter, cap and flashing | 10% | Estimating practice: starter at 5 nails per piece, caps at 2 per cap, drip edge at 12 in centers |
| Nail specification | Galvanized steel, 12-gauge minimum, ⅜-in head | IRC R905.2.5 and ASTM F1667 |
Assumptions last reviewed October 7, 2026.
The calculator does not count the fasteners for underlayment (cap nails or staples, counted by the underlayment calculator) or for metal roofing, which uses screws. It does not know whether your roof is in a high-wind region: that is on the manufacturer’s wind map and in your local code. The guide to roofing nails and nailing patterns covers the nailing zone, the six-nail pattern and what an overdriven nail does to a warranty.
Two worked examples
A standard roof with coil nails
Twenty-two squares of architectural shingles including waste, four nails per shingle, 1¼-inch coil nails at 200 per pound, boxes of 7,200, 10% extra.
- Shingles: 22 × 64 = 1,408
- Field nails: 1,408 × 4 = 5,632
- With extras: 5,632 × 1.10 = 6,195 nails
- Weight: 6,195 ÷ 200 = 31 lb
- Boxes: 6,195 ÷ 7,200 = 0.86, rounded up to 1 box of coil nails
One box covers the roof with a thousand nails spare, which is the right amount of spare for a gun that occasionally misfires.
A high-wind roof hand-nailed with 1½-inch nails
Thirty-four squares of three-tab shingles, six nails per shingle for a high-wind region, 1½-inch nails at 165 per pound, 50-pound boxes.
- Shingles: 34 × 80 = 2,720
- Field nails: 2,720 × 6 = 16,320
- With extras: 16,320 × 1.10 = 17,952 nails
- Weight: 17,952 ÷ 165 = 108.8 lb
- Boxes: a 50-lb box holds 8,250 nails, so 17,952 ÷ 8,250 = 2.18, rounded up to 3 boxes
Three-tab shingles at six nails take almost three times the nails of the first example for a roof only 55% larger: more shingles per square and half again as many nails per shingle.
Where to find your inputs
Squares. From the shingle calculator, including waste, so the nails cover the shingles you actually buy rather than the bare roof area.
Nail length. Add the shingle thickness to the ¾ inch the nail must penetrate into the deck. For standard shingles on a bare deck that gives 1¼ inch; over an old layer or with thick shingles 1½; through a ridge vent 2 to 2½.
Nails per pound and box size. On the box. Hand nails come in 1, 5, 30 and 50 pound boxes; coil nails for guns in boxes of 7,200 (60 coils of 120). If your coil box differs, divide its count by the number of boxes you need and adjust.
Common mistakes
- Nailing four where six are required. High-wind regions, very steep pitches and the enhanced warranty all need six. The cost difference on this calculator is a box or two of nails.
- Short nails on a reroof. Over one old layer a 1¼-inch nail barely reaches the deck. Step up to 1½ inch.
- Overdriving with a gun. A nail head driven through the mat cuts the shingle and voids the warranty. Set the gun so the head sits flush, and check the first few on every pitch change.
- Nailing above the nail line. High nails miss the shingle below and leave the course unsealed. Nail in the marked zone, through both layers of an architectural shingle.
- Staples. The code and every manufacturer require roofing nails for asphalt shingles. Staples are for underlayment.
- Forgetting the extras. Starter at five nails a piece, caps at two, drip edge every foot: roughly a tenth of the field count. Leave the extra at 10%.
Questions people ask
- How many nails per square of shingles?
- Four nails per shingle in the standard pattern. Architectural shingles run about 64 to the square, so 256 nails; three-tab shingles run about 80, so 320. In high-wind regions and on pitches above 21/12 manufacturers require six nails per shingle, 384 or 480 per square. Add about a tenth for the starter, caps and flashing.
- What length roofing nail should I use?
- The nail must penetrate ¾ inch into the deck or go through it. On a bare ½-inch plywood or OSB deck with one layer of standard shingles, 1¼ inch is right; thick architectural or designer shingles, or shingling over one old layer, need 1½ inch; cap over a ridge vent needs 2 to 2½ inches. One-inch nails suit only thin three-tab on a new deck.
- How many roofing nails are in a pound?
- About 250 one-inch, 200 1¼-inch, 165 1½-inch, 145 1¾-inch and 125 two-inch 11-gauge galvanized roofing nails per pound. The box states its count; enter it in the nails-per-pound field if it differs. A 50-pound box of 1¼-inch nails therefore holds around 10,000 nails, and a box of coil nails for a gun holds 7,200.
- How many pounds of nails for a roof?
- The calculator's default roof of 22 squares of architectural shingles at four nails per shingle plus 10% for extras needs 6,195 nails, which is 31 pounds of 1¼-inch nails, or one box of 7,200 coil nails. At six nails on three-tab shingles the same squares need about 11,600 nails and 70 pounds of 1½-inch nails.
- Can I use staples for shingles?
- Not for asphalt shingles. Manufacturers and the International Residential Code (R905.2.5) require galvanized steel, stainless, aluminum or copper roofing nails with a minimum 12-gauge shank and a ⅜-inch head; staples void the warranty and fail in wind. Plastic-cap staples are for synthetic underlayment, not shingles.
- Where exactly do the nails go?
- In the nailing zone marked on the shingle, which on architectural shingles is a strip where the two layers overlap so the nail passes through both. Nails are driven straight and flush, never angled, overdriven or underdriven; a nail driven through the mat lets the shingle slide, and a high nail cuts into the shingle above.