Nail Size Chart: Penny Sizes, Length and Diameter

Nails in the US are still sold by penny size, written with a “d”: a 16d nail is 3-1/2 inches long, an 8d is 2-1/2 inches. The penny number tells you the length, but not the diameter, and the diameter depends on the kind of nail. A 16d common nail is 0.162 in thick, a 16d box nail only 0.135 in. The chart below gives the length and the shank diameter of every size of common, box and threaded nail. All of them are taken from the USDA Wood Handbook, Tables 8-1 to 8-3. A second table shows how hard each common nail is to pull out of fifteen woods, worked out from the Handbook’s withdrawal equation. To pick a nail for two boards you are joining, use the screw and nail size calculator.

Nail size chart: penny size, length and diameter

Reading the chart

• Common nails are the thick framing nail. Lengths run from 2 in (6d) to 6 in (60d), and the diameter climbs with the length, from 0.113 in at 6d to 0.262 in at 60d.
• Box nails are the same length as common nails of the same penny size but thinner, so they split thin or dry boards less: an 8d box nail (0.113 in) is the same diameter as a 6d common.
• Threaded nails (ring-shank or spiral-shank) are thinner again, but hold better than their diameter suggests; see “Ring and spiral shanks” below.
• Coated sinkers and coolers are not in the table. The Handbook notes that cement-coated nails of a given penny size are about 1/8 in (3.2 mm) shorter and slightly thinner than common nails, so a “16d sinker” is roughly 3-1/4 in, not 3-1/2.
• Specify length and diameter, not just penny size. The Handbook calls penny sizes “obsolete” for exactly this reason, and warns that some imported nails do not match the table. Collated nails for framing guns are usually labelled by length and shank diameter (for example 3-1/4 x 0.131 in), and a box of “16d” gun nails is often thinner than a 16d common. Where a plan or a code calls for a size, compare the diameter on the box with the chart.

How much holding power: withdrawal by wood species

The Handbook gives one equation for pulling a smooth common nail straight out of the side grain of dry wood, soon after it was driven: p = 7,850 G^5/2 D L, where p is the maximum load in pounds, G the specific gravity of the wood (ovendry, at 12% moisture content), D the nail diameter and L the depth of penetration into the piece that holds the point, both in inches. Because G is raised to the power 2.5, density matters far more than nail size. The table gives the result per inch of penetration; multiply by the depth your nail actually reaches into the second piece.

Worked example: 16d common into a Douglas-fir plate

A 16d common nail (3-1/2 in long, 0.162 in) driven through a 1-1/2 in stud into a Douglas-fir plate leaves 2 in of nail in the plate. Coast Douglas-fir has G = 0.48. Then p = 7,850 x 0.48^2.5 x 0.162 x 2 = 406 lb. A 16d box nail (0.135 in) in the same spot gives 338 lb, about 17% less, because withdrawal is proportional to the diameter.

Change the wood and the number moves much more. The same nail in northern red oak (G = 0.63) is 4.3 times as hard to pull as in eastern white pine (G = 0.35), even though oak is less than twice as dense. Lighter woods are not ruled out, though: the Handbook points out that they split less, so you can make up for the lower grip with a longer, thicker nail or more of them.

What lowers or raises the holding power

• Moisture cycling. A smooth nail driven into green wood that then dries, or into dry wood that is wetted and dried again, can lose most of its grip: the Handbook reports withdrawal as low as 25% of the value just after driving.
• End grain. A nail driven into the end of a board holds only 50% to 75% as well as one in the side grain.
• Ring and spiral shanks. Annularly threaded (ring-shank) nails can hold about twice as well as common nails when first driven, and the Handbook found about four times as much where the wood’s moisture content changes. That is why ring-shank nails are used for subfloors, siding and other parts that get damp.
• Coatings. Cement coatings help in soft woods at first, but the gain mostly disappears within about a month, and in dense woods such as maple or oak the coating is scraped off on the way in. Galvanizing is for corrosion resistance; it does not reliably add grip.
• Pilot holes. A lead hole of about 90% of the nail diameter slightly increases withdrawal resistance and stops splitting, especially in dense hardwoods.
• Clinching. Bending over the point of a nail that comes through the back gave 45% to 170% more withdrawal resistance in the Handbook’s tests when the nails were pulled soon after driving, and far more in green wood that then dried.

Toenailing

For toenails the Handbook lists four things that gave the strongest joints in tests: use the largest nail that does not split the wood; start the nail about one third of its length from the end of the piece; drive it at about 30 degrees to the piece being attached; and bury the whole shank without battering the wood with the hammer.

Corrosion and treated lumber

In pressure-treated lumber, plain steel nails corrode. The Handbook reports that copper, silicon bronze and 300-series stainless steel nails performed well in CCA- and ACA-treated wood, and 300-series stainless in copper azole and ACQ. Nails and metal connectors such as joist hangers should be the same metal, otherwise galvanic corrosion speeds up. For cedar or redwood siding with a clear finish, use stainless steel, aluminium or hot-dipped galvanized nails to avoid black stains. For treated lumber outdoors, follow the fastener requirements of the lumber treater, the connector maker and your local code.

Safety and structural use

The withdrawal figures are average loads at which nails pulled out in laboratory tests. They are not allowable design values, and design values in the National Design Specification for Wood Construction (NDS) are far lower. Do not use this page to size the nailing for anything structural (framing, decks, sheathing, guards, roofs). For that, use the nailing schedule in your local building code, the connector maker’s instructions, or a licensed engineer.

Frequently asked questions

How long is a 16d nail?

3-1/2 inches (88.9 mm). A 16d common nail is 0.162 in thick; a 16d box nail is 0.135 in; a 16d threaded nail is 0.148 in (Wood Handbook Tables 8-1 to 8-3).

How long is an 8d nail?

2-1/2 inches (63.5 mm). The 8d common is 0.131 in in diameter and the 8d box nail 0.113 in.

What does the d in nail sizes mean?

It stands for penny, from the Latin denarius, the coin abbreviated “d” in old British money. The system survives only as a size name; the Wood Handbook recommends giving the length and diameter instead.

What is the difference between common and box nails?

Same length, smaller diameter. Box nails split less but hold less: withdrawal resistance is proportional to diameter, so a 16d box nail holds about 17% less than a 16d common in the same wood.

Do ring-shank nails really hold better?

Yes. The Wood Handbook reports roughly double the withdrawal resistance of a common nail when first driven, and about four times as much in wood whose moisture content changes over time.

Sources and method

Nail dimensions are copied from the Handbook tables (a public-domain US Government work). Withdrawal values are computed by us from the Handbook equation, so you can check any cell by hand.

1. USDA Forest Service, Forest Products Laboratory. Wood Handbook: Wood as an Engineering Material, General Technical Report FPL-GTR-190 (2010), chapter 8, Fastenings (D. R. Rammer). A US Government publication in the public domain. Tables 8-1, 8-2 and 8-3; Equation 8-1; sections on seasoning, nail form, corrosion, driving, toenailing and clinching.
2. Specific gravity of each species: Wood Handbook FPL-GTR-190, Tables 5-3b and 5-5b (ovendry weight, volume at 12% moisture content), the same data as our wood species database.
3. Nail selection rule (length about 3 x the piece being fastened): our screw and nail size calculator.

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Last reviewed: 24 October 2026. How we build and check our data: methodology and corrections. Spotted an error? Please let us know.