Nail Size Chart: Penny Sizes, Lengths, Diameters and Gauges

Penny nail size chart (common and box nails)

The "d" stands for denarius, the Roman penny. The system dates back to England, where nails were priced per hundred, so a hundred 10-penny nails cost 10 pence. Today the penny size fixes the length only. Common nails are the thick framing standard; box nails are the same length but thinner, which reduces splitting in dry or narrow lumber.

Count per pound varies by maker, head style and coating by roughly 10%, so buy by weight with a margin. For 2d through 10d, length in inches equals the penny number divided by 4, plus 1/2 in: 8 ÷ 4 + 1/2 = 2 1/2 in. Above 10d the steps are irregular, so use the chart.

Sinker, finish, brad and other nail types

Many nails borrow the penny name but not the common-nail dimensions. Always read the length and diameter on the box, especially where a building code or an engineered connector specifies the nail.

Under IRC Section R905.2.5, asphalt-shingle nails must have at least a 12-gauge (0.105 in) shank and a 3/8 in (9.5 mm) head, and must reach at least 3/4 in into the roof deck or pass through it. That is why 1 1/4 in roofing nails are standard on new roofs and 1 3/4 in nails are used when shingles go over an existing layer.

Nail gauge chart

Gauge is an old wire-drawing number: the more times wire is drawn, the thinner it gets and the higher the number. Nail makers use the steel wire gauge (Washburn & Moen), not the American Wire Gauge used for electrical wire.

The thicker the nail, the more it resists bending and shear, and the more likely it is to split thin or dry wood near an edge. A 23-gauge pin holds only while glue sets; a 15-gauge finish nail holds heavy baseboard on its own.

Nail gun nail sizes

Gun nails are sold by length × diameter, and a "16d" gun nail is usually thinner than a hand-driven 16d common nail. Check that a nailer's nail meets the code or engineering requirement before you swap one for the other.

Code fastening schedules list gun-nail equivalents. For example, IRC Table R602.3(1) allows a stud end-nailed through a plate with two 16d common nails (3 1/2 × 0.162 in), three 10d box nails (3 × 0.128 in) or three 3 × 0.131 in nails.

How to choose the right nail length

1. Measure the piece being fastened. That is the board the nail passes through, not the one it ends in.
2. Multiply by three. The nail should be about three times that thickness, so two-thirds of its length grips the base. For 3/4 in trim, that is 2 1/4 in: a 7d or 8d nail.
3. Check it will not poke through. Total material thickness must exceed the nail length, or the point will show on the other side. Two face-nailed 2x boards are 3 in thick (2 × 1 1/2 in, see actual lumber sizes), so a 10d (3 in) nail is the longest that will not stick out the far side.
4. Pick the diameter for the wood. Use box or sinker nails near board ends or in dry softwood; use common nails where strength matters and the code calls for them.
5. Pick the coating. Hot-dip galvanized or stainless for pressure-treated lumber and outdoor work such as decks; bright (uncoated) nails only indoors.

Common nail uses by size

• 2d-3d (1-1 1/4 in): thin paneling, picture frames, small crafts.
• 4d-6d (1 1/2-2 in): 1/2 in plywood and OSB, shelving, light trim.
• 8d (2 1/2 in): wall and roof sheathing, subfloor, toenailing studs.
• 10d-12d (3-3 1/4 in): face-nailing two 2x boards, toenailing joists.
• 16d (3 1/2 in): the framing nail: end-nailing studs through plates, joists through rims.
• 20d-60d (4-6 in): heavy timbers, landscape ties, built-up beams.

Nails shear well but pull out more easily than threaded fasteners. Where a joint must resist pulling apart, or where you may need to disassemble it, use screws. For drywall, screws have largely replaced nails because they do not pop as framing dries. A pouch-style tool bag keeps two or three nail sizes separate on the job.

Frequently asked questions