Nail size chart: penny sizes, lengths and diameters

Nail size chart, 3d to 60d

Common and box nail lengths, diameters and gauges are from Wood Handbook Tables 8–1 and 8–2. Sizes the Handbook does not list (7d common; 12d, 30d and 40d box) and all sinker nails are from NDS Table L4. Where both sources cover a size they agree, except the 60d common nail noted below.

Not listed: 2d (Not listed in Wood Handbook Tables 8–1 or 8–2 or NDS Table L4. ASTM F1667 covers it but was not available for verification.) 9d (Not listed in Wood Handbook Tables 8–1 or 8–2 or NDS Table L4.) Finish nails and approximate counts per pound are also omitted, because neither source tabulates them.

What the "d" in nail sizes means

The d marks a penny size, and the penny size works as a length code. Reading down the chart, every penny from 3d to 10d adds 1/4 in. to a 1/2 in. base, so a 6d nail is 1/2 + 6 × 1/4 = 2 in. Above 10d the pattern breaks: 12d is 3-1/4 in., 16d is 3-1/2 in., 20d is 4 in., and each further 10 pennies adds 1/2 in. up to 60d at 6 in.

The Wood Handbook says penny sizes should be used cautiously, describes them as obsolete, and recommends specifying nails by length and diameter, because international producers sometimes do not follow the standard dimensions. Nail gauge numbers also run the opposite way to screw gauges: the higher the gauge, the thinner the wire.

Common, box and sinker nails

• Common nails have the thickest shank for each size. Most of the Wood Handbook's load equations are written for bright, smooth, common steel wire nails.
• Box nails are generally the same length as common nails but with a slightly smaller diameter (Table 8–2).
• Sinkers and other cement-coated nails are, per the Handbook, about 1/8 in. shorter and of smaller diameter than common nails of the same penny size. In NDS Table L4 sinkers are 1/8 in. shorter up to 12d and 1/4 in. shorter from 16d up.
• Threaded nails (helically or annularly threaded) generally have smaller diameters than common nails of the same penny size; the Handbook lists them separately in Table 8–3.

Choosing nail length

A nail holds by the length driven into the piece receiving its point. The Wood Handbook recommends penetration of at least 10 nail diameters in dense woods (specific gravity above 0.61) and 14 diameters in low-density woods (below 0.42), with straight-line interpolation between. It also says the side member should be about half as thick as the penetration. The NDS minimum penetration is 6 diameters.

nail length ≥ side-member thickness + (10 to 14) × nail diameter

Using NDS assigned specific gravities, Spruce-Pine-Fir (G 0.42) falls at the low-density end and needs 14 diameters; Southern Pine (G 0.55) works out to 11.3 diameters. For wood species values, see the species density table.

Worked examples

1. Nailing a 3/4 in. board to framing

A nominal 1× board is 3/4 in. (19.1 mm) thick (PS 20 Table 3). An 8d common nail is 2-1/2 in. long and 0.131 in. thick, leaving 1-3/4 in. (44.5 mm) in the framing. That is 13.4 diameters, slightly below the Wood Handbook's target of about 14 diameters for low-density Spruce-Pine-Fir but well above the NDS minimum of 6. The board is 0.43 times the penetration, close to the Handbook's one-half.

2. Face-nailing a 2× member to a doubled 2×

The side member is 1-1/2 in. thick and the receiving member is two plies, or 3 in. The table compares four nails in Spruce-Pine-Fir, where the Handbook target is 14 diameters.

A thinner nail reaches more diameters for the same length, which is why only the 16d box passes. The 16d common reaches 12.3 diameters and the shorter 16d sinker 11.8. That target governs how much of its ultimate strength a nail can develop; it is not a code requirement. All four exceed the NDS minimum of 6 diameters. A thicker nail also carries more load, so for framing use the nail size and spacing in the applicable building-code fastening schedule.

Pilot holes, clinching and toe-nailing

The Wood Handbook reports that nails driven into lead holes about 90% of the shank diameter have somewhat greater withdrawal resistance than nails driven without them, and that lead holes prevent or reduce splitting, particularly in dense species. The NDS limits bored holes to 90% of the nail diameter where G is above 0.6 and 75% where G is 0.6 or less. For an 8d common nail in oak, 90% of 0.131 in. is 0.118 in., so a 7/64 in. (0.109 in.) bit stays within the limit.

Clinching (bending over a point that protrudes through the far side) makes a smooth nail considerably harder to pull out, according to the Handbook. For toe-nails, the NDS specifies driving at about 30° to the member, started about one-third of the nail length from the member end.

Nails or screws?

The Handbook notes that variations in the wood, the nail and the conditions of use affect a nail's withdrawal resistance much more than its lateral resistance, so nails are better suited to joints loaded sideways. Where a joint is pulled apart, or must come apart again, screws hold better: compared through the Handbook's withdrawal equations, a wood screw of the same diameter and penetration resists roughly three times the withdrawal load of a smooth nail in Spruce-Pine-Fir. See the screw size chart for gauges and pilot holes. To place nails without splitting the wood, the fastener spacing calculator gives minimum spacing and edge and end distances for each diameter.

Common mistakes

• Assuming the same penny means the same nail. A 16d common, box and sinker differ in diameter, and the sinker is 1/4 in. shorter.
• Nailing through into thin air. Check that the nail length minus the side member stays inside the receiving member, or plan to clinch it.
• Oversizing pilot holes. Keep lead holes at or below the NDS limits of 75% or 90% of the nail diameter.
• Relying on nails in withdrawal. Use screws, or arrange the joint so the load acts across the nail.
• Buying by penny size alone. Imported nails may not match these dimensions; read the length and diameter on the pack.

Common questions