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Nail Size Chart
Quick answer: Above 4d, length = (penny ÷ 4) + 0.5 inches. So 8d = 2.5″ and 16d = 3.5″. The penny number sets length only — diameter depends on whether it is a common, box or finish nail.
Every penny size from 2d to 60d with length, gauge and diameter, the difference between common and box nails, and the IRC nailing schedule for framing.
Nail size chart (penny sizes)
Nails are still sold by the “penny” system, abbreviated d from the Roman denarius. It is a length scale, not a diameter scale — and above 4d the relation is simple: length in inches = (penny ÷ 4) + 0.5. An 8d nail is 8÷4 + 0.5 = 2.5″.
| Penny | Length (in) | Gauge | Diameter (in) | Typical use |
|---|---|---|---|---|
| 2d | 1 | 15 | 0.072 | Trim, small finish work |
| 3d | 1.25 | 14 | 0.080 | Lath, shingles, light trim |
| 4d | 1.5 | 12.5 | 0.099 | Trim, casing, small framing |
| 5d | 1.75 | 12.5 | 0.099 | Trim and light sheathing |
| 6d | 2 | 11.5 | 0.113 | Sheathing, subfloor, light framing |
| 7d | 2.25 | 11.5 | 0.113 | Sheathing |
| 8d | 2.5 | 10.25 | 0.131 | Framing, sheathing, toe-nailing |
| 10d | 3 | 9 | 0.148 | Framing, joist hangers |
| 12d | 3.25 | 9 | 0.148 | Framing, heavy sheathing |
| 16d | 3.5 | 8 | 0.162 | Standard stud-to-plate framing |
| 20d | 4 | 6 | 0.192 | Heavy framing, ledgers |
| 30d | 4.5 | 5 | 0.207 | Heavy timber |
| 40d | 5 | 4 | 0.225 | Heavy timber |
| 60d | 6 | 2 | 0.263 | Heavy timber, bridging |
Diameters are for common nails. Box nails at the same penny size are one to two gauges thinner, and finish nails thinner still. Note that 4d/5d, 6d/7d and 10d/12d share a gauge — the length changes but the shank does not.
Common, box, sinker and finish
| Type | Shank | Head | Use |
|---|---|---|---|
| Common | Thickest | Large flat | Framing where shear strength governs |
| Box | 1–2 gauges thinner | Flat | Sheathing and thin stock — splits less |
| Sinker | Between the two | Coated, slightly countersunk | Framing; the coating heats and grips as it drives |
| Finish | Thin | Small barrel head | Trim — set below surface and fill |
| Brad | Thinnest (18ga) | Almost none | Delicate trim, small mouldings |
| Duplex | Common | Double head | Temporary bracing and formwork — pulls out cleanly |
What the framing schedule actually calls for
| Connection | Nail | Quantity / spacing |
|---|---|---|
| Stud to sole plate, toe-nail | 8d common | 4 per stud |
| Stud to sole plate, end-nail | 16d common | 2 per stud |
| Double top plate | 16d common | 16″ on centre |
| Rim joist to joist | 16d common | 3 per joist end |
| Wall sheathing, 1/2″ | 6d common | 6″ edges, 12″ field |
| Roof sheathing, 1/2″ | 8d common | 6″ edges, 12″ field |
| Subfloor, 3/4″ | 8d common | 6″ edges, 12″ field |
Values follow IRC Table R602.3(1). High-wind and seismic regions amend this schedule — check your local adoption before framing.
Nail gun collation
Pneumatic framing nailers are sold as 21°, 28° or 30–34°. The angle describes the collation strip, not the nail. Rough guide: 21° takes full round-head plastic-collated nails and satisfies code everywhere; 28° and 30–34° usually take clipped-head nails, which some jurisdictions restrict in high-wind zones. Check before you buy the gun, not after.
Frequently asked questions
How long is a 16d nail?
3.5 inches. The penny-to-length relation above 4d is length = (penny ÷ 4) + 0.5, so 16 ÷ 4 + 0.5 = 3.5 in. A 16d common nail is 8 gauge, 0.162 in diameter.
What does the d in nail sizes mean?
It stands for denarius, a Roman coin, and survives from an English pricing convention — the cost per hundred nails. It now indicates length only, not diameter.
What size nails for 2x4 framing?
16d common (3.5 in) for end-nailing studs through the plate, and 8d common (2.5 in) for toe-nailing. IRC Table R602.3(1) gives the full schedule.
Are box nails and common nails interchangeable?
Not in structural work. A box nail is one to two gauges thinner at the same penny size, so it carries less shear. Substituting box for common in a framing connection is a code violation, though box nails are preferred in thin stock precisely because they split it less.