What "16d" actually means, every penny size from 2d to 60d in inches and millimetres, and which nail does which job.
| Penny size | Length | Length (mm) | Common-nail Ø | Typical use |
|---|
Diameters are for common nails (ASTM F1667); box and sinker nails of the same penny size are thinner, finish nails thinner still. The two highlighted rows are the sizes to know.
3-1/2″ long (89 mm). A 16d common is 0.162″ in diameter and is the standard framing nail; a 16d "sinker" is slightly thinner and shorter but drives easier — check your local code for structural work.
Penny — from the Latin denarius. It originally meant the price of 100 nails in old English pennies; longer nails cost more. Now it's purely a length designation.
Framing: 16d (3-1/2″). Sheathing and subfloor: 8d (2-1/2″). Doubling studs / joining plates: 10d–12d. Trim and finish work: 4d–8d finish nails. Roofing uses its own short, big-headed roofing nails, not penny-sized commons.
Nails have better shear strength and flex without snapping — that's why framing codes call for nails. Screws grip far better in withdrawal (pull-out) but are brittle in shear. Structure: nails. Pull-tight and removable work: screws.