Nail Size Chart: Penny Sizes Explained

How the penny system works, the length and thickness of every common nail size from 2d to 60d, and which size to use for framing, sheathing, decking and trim.

Updated

Common nails from 2d to 20d drawn to scale side by side, from a 1 inch 2d nail to a 4 inch 20d nail, each labeled with its penny size and length

Nail sizes in the US use the old penny system, written with a d: 8d is “eight-penny”, 16d is “sixteen-penny”. The number tells you the length. From 2d to 10d, each step adds ¼ inch: a 2d nail is 1 inch long and a 10d nail is 3 inches.

Nail size chart

Diameters are for common nails, the thick, general-purpose nails used for framing (ASTM F1667). Box nails and sinkers of the same penny size are thinner.

Size Length (in) Length (mm) Diameter (in) Diameter (mm)
2d 1 25 0.072 1.8
3d 1¼ 32 0.080 2.0
4d 1½ 38 0.098 2.5
5d 1¾ 44 0.098 2.5
6d 2 51 0.113 2.9
7d 2¼ 57 0.113 2.9
8d 2½ 64 0.131 3.3
9d 2¾ 70 0.131 3.3
10d 3 76 0.148 3.8
12d 3¼ 83 0.148 3.8
16d 3½ 89 0.162 4.1
20d 4 102 0.192 4.9
30d 4½ 114 0.207 5.3
40d 5 127 0.225 5.7
50d 5½ 140 0.244 6.2
60d 6 152 0.263 6.7

Above 10d, the steps get uneven, so it’s worth keeping the chart handy. In the rest of the world, nails are simply sold by length and diameter in millimeters, such as 90 × 3.75 mm.

Which nail size to use

Job Typical nail
Framing walls (through a 2x into a 2x) 16d common or 16d sinker
Toe-nailing studs at an angle 8d or 10d
Plywood or OSB sheathing and subfloor 8d
Deck boards (1 in thick) 10d galvanized or stainless
Fence pickets 6d or 8d galvanized
Baseboard and door trim 6d or 8d finish nails
Small trim, shoe molding 4d finish nails, or brads
Roof shingles 1¼ in roofing nails

A good rule for nailing one board to another: the nail should be about three times as long as the thickness of the board you’re nailing through, so two-thirds of it holds in the second piece. Through a 1½ inch 2x4, that’s about 4 inches, but 3½ inch 16d nails are the norm because they don’t poke out the other side of a second 2x4.

Nail types

  • Common nails have a thick shank and a large flat head, for strength in framing.
  • Box nails are thinner, so they’re less likely to split thin wood, but they hold less.
  • Sinkers are coated, slightly thinner and shorter framing nails that drive easily.
  • Finish nails have a small head that can be set below the surface and filled, for trim.
  • Galvanized or stainless nails resist rust, so use them outdoors and in treated lumber.

Measuring a nail

Measure from the underside of the head to the tip, with a ruler or tape measure, then find the length in the chart. Diameter is easiest to compare by laying the nail next to one you know. To convert lengths, use inches to mm.

For the lumber you’re nailing, see lumber sizes: actual vs nominal.

More DIY charts: screw and bolt sizes · washer sizes · drill bit sizes · sandpaper grit · wrench sizes.

Frequently asked questions

What does the d mean in nail sizes?

It stands for penny. The d comes from denarius, a Roman coin, which was the abbreviation for a penny in old English money. The size is thought to have described the price of 100 nails, so 100 of the 10d nails cost ten pence. Today it simply means length: a 10d nail is 3 inches long.

How long is a 16d nail?

3½ inches (89 mm). A 16d common nail is 0.162 in thick; a 16d sinker, the coated framing nail sold for nail guns and hand nailing, is a little shorter at 3¼ inches and thinner at 0.148 in.

What size nail for framing a 2x4 wall?

16d nails, 3½ inches, for nailing through one 2x4 into another, such as through a plate into a stud. 8d or 10d nails are used for toe-nailing at an angle. Always check your local building code, which can specify the nail size and spacing.

How long is an 8d nail?

2½ inches (64 mm). It's the usual size for nailing ½ inch and ¾ inch plywood or OSB sheathing and subfloors to framing.

More measuring guides