Nail Size Converter
Convert nail penny sizes (d) to length in inches and millimeters.
Look up common nail sizes and their typical uses.
Select a penny size — see the nail length and typical use.
Nail Details
Nail sizes are measured in “penny” (d) — an old English system.
The “d” in nail sizes stands for “denarius” (a Roman coin). Originally, it was the cost in pennies for 100 nails.
Common nail sizes:
| Penny | Length (in) | Length (mm) | Common Use |
|---|---|---|---|
| 2d | 1.00 | 25.4 | Small trim, crafts |
| 3d | 1.25 | 31.8 | Light trim |
| 4d | 1.50 | 38.1 | Small trim, shingles |
| 6d | 2.00 | 50.8 | Siding, light framing |
| 8d | 2.50 | 63.5 | Sheathing, subflooring |
| 10d | 3.00 | 76.2 | General framing |
| 12d | 3.25 | 82.6 | Framing, sheathing |
| 16d | 3.50 | 88.9 | Wall framing (most common) |
| 20d | 4.00 | 101.6 | Heavy framing |
| 30d | 4.50 | 114.3 | Heavy structural |
| 40d | 5.00 | 127.0 | Very heavy structural |
| 60d | 6.00 | 152.4 | Timber framing |