EstimatorKitPenny sizes
Nail size chart — the penny system from 2d to 60d
A penny size is a length and nothing else: 2d is one inch, every step up adds a quarter inch as far as 10d at three inches, and the scale then jumps in half inches to 60d at six. This chart carries all 45 sizes across common, box, sinker, finish and casing nails with the shank diameter and wire gauge that actually decide what a nail holds, plus a calculated nails-per-pound figure so a count off a fastening schedule can be turned into boxes. The panel above the table works both ways — measure the nail on your bench to name it, or name the nail and get the weight to order.
- 2d to 60d
- 45 nails, five patterns
- Nails per pound
Inches unless you say otherwise: 2 1/2, 3.25, 82 mm. Measure under the head, not over it.
Length alone gets you to a penny size. What separates the nails at that length is the wire gauge, so the list below is ordered thinnest first — hold the shank against the diameters until one matches.
2.5 in is
- 8d finish2 1/2"0.098 in · 12 1/2 ga
- 8d box2 1/2"0.113 in · 11 1/2 ga
- 8d casing2 1/2"0.113 in · 11 1/2 ga
- 8d common2 1/2"0.131 in · 10 1/4 ga
- 8d sinker2 3/8"0.113 in · 11 1/2 ga
Thick smooth shank and a flat head — the structural nail the fastening schedule is written around.
| Penny | Length | Shank | Wire gauge | Per pound |
|---|---|---|---|---|
| 2d | 1" | 0.072 in | 15 | 866 |
| 3d | 1 1/4" | 0.08 in | 14 | 561 |
| 4d | 1 1/2" | 0.098 in | 12 1/2 | 312 |
| 5d | 1 3/4" | 0.098 in | 12 1/2 | 267 |
| 6d | 2" | 0.113 in | 11 1/2 | 176 |
| 7d | 2 1/4" | 0.113 in | 11 1/2 | 156 |
| 8d | 2 1/2" | 0.131 in | 10 1/4 | 105 |
| 9d | 2 3/4" | 0.131 in | 10 1/4 | 95 |
| 10d | 3" | 0.148 in | 9 | 68 |
| 12d | 3 1/4" | 0.148 in | 9 | 63 |
| 16d | 3 1/2" | 0.162 in | 8 | 49 |
| 20d | 4" | 0.192 in | 6 | 30 |
| 30d | 4 1/2" | 0.207 in | 5 | 23 |
| 40d | 5" | 0.225 in | 4 | 18 |
| 50d | 5 1/2" | 0.244 in | 3 | 14 |
| 60d | 6" | 0.263 in | 2 | 11 |
What the fastening schedule asks for
Reproduced from IRC Table R602.3(1), 2021 edition. This is the published table, not a verdict on your frame: a local amendment, an engineered detail or the inspector standing in front of it overrides every row here.
| Stud to sole plate, toe nail | 4 × 8d common (2 1/2 in × 0.131) |
|---|---|
| Stud to sole plate, end nail | 2 × 16d common (3 1/2 in × 0.162) |
| Top plate to stud, end nail | 2 × 16d common |
| Double top plates, face nail | 16d common at 16 in on center |
| Sole plate to joist or blocking, face nail | 16d common at 16 in on center |
| Doubled studs, face nail | 10d common (3 in × 0.148) at 24 in on center |
| Built-up header, two pieces | 16d common at 16 in on center along each edge |
| Joist to sill, top plate or girder, toe nail | 3 × 8d common |
| Ceiling joist to plate, toe nail | 3 × 8d common |
| Rafter or roof truss to plate, toe nail | 3 × 10d common |
| Blocking between joists or rafters, toe nail | 3 × 8d common |
| Wall sheathing 3/8 to 1/2 in | 6d common, 6 in at edges and 12 in in the field |
| Wall sheathing 19/32 to 1 in | 8d common, 6 in at edges and 12 in in the field |
| Subfloor and roof sheathing 3/4 in | 8d common, 6 in at edges and 12 in in the field |
Lengths and shank diameters follow the traditional penny table standardized in ASTM F1667: 2d is one inch and each penny step to 10d adds a quarter inch, which is why the quarter-inch step stops at 10d and 12d, 16d, 20d and beyond move in half inches. Nails per pound is calculated, not transcribed: shank volume × 0.2836 lb/in³ reproduces the published bright common counts within about three percent, because the head and the point taper very nearly cancel. Galvanized, coated and ring-shank nails all run heavier, so treat the column as a purchase estimate rather than a count you can audit a box against.
Nail questions
Why are nails measured in pennies?
Because the size originally quoted the price of a hundred of them in fifteenth-century England, where a hundred tenpenny nails cost ten pence. The abbreviation is a 'd' rather than a 'p' because the English penny was the Roman denarius, and 'd' stayed the symbol for it right up to decimalization in 1971. A competing account has the number describing the weight of a thousand nails instead; either way, the price relationship stopped meaning anything centuries ago and the label survived as a pure size code.
How long is a 16d nail?
Three and a half inches, if it is a 16d common or a 16d box. A 16d sinker is 3 1/4 in — the coated framing nail sold in bulk buckets is a quarter inch shorter than the size on the label, and it shares that length with the 12d sinker. This matters when a plan calls for penetration into the receiving member, which is measured from the far face of the piece being fastened rather than from the head.
Can I use box nails where the plan says common?
No, not without approval. At the same penny size a box nail is one to two wire gauges thinner — 0.135 in against 0.162 in at 16d — and the lateral design value in the code tables is driven by that diameter, so substituting downward quietly reduces the connection's rated capacity. The substitution runs the other way as well: a common nail where a box was specified splits thin material that the thinner shank would have survived.
Which nails go into pressure-treated lumber?
Hot-dip galvanized to ASTM A153 or stainless, and nothing else outdoors. The copper-based preservatives that replaced CCA are considerably more corrosive to bare and electroplated steel, and an electroplated nail in a treated ledger can lose its coating in a few seasons — the failure shows up as rust streaks on the face long before the fastener is actually gone. Stainless is the answer near salt water and under cedar and redwood, whose own tannins attack zinc.
What nail does sheathing take?
8d common at 6 in on the panel edges and 12 in in the field for anything 19/32 in and up, dropping to 6d for 3/8 to 1/2 in wall sheathing. The edge spacing is the number that gets missed: a panel nailed at 12 in all over has roughly half the shear capacity the schedule assumes, and it is invisible once the siding goes on. Shear wall details on an engineered plan tighten the edge nailing further, sometimes to 3 in, and that detail beats the general table.
What a nail actually holds
The ‘d’ is a denarius. English prices were written in Roman abbreviations long after the Romans left, so the penny took a d and kept it until Britain decimalised in 1971 — and a fifteenth-century ironmonger charging tenpence for a hundred nails gave us the tenpenny nail, which is three inches long and has had nothing to do with money for five hundred years. What survived is the interval rather than the price: from 2d to 10d the scale is a metronome, a quarter of an inch per step, which is the only reason a code written in penny sizes is still readable. Above 10d it loses its nerve and starts moving in half inches, which is why 11d, 13d and 15d do not exist while 12d, 16d and 20d are everywhere.
Length is what the label tells you and diameter is what the joint feels. A nail resists being pulled sideways in rough proportion to its shank diameter, which is why the code tables specify wire gauge alongside the penny size and why the difference between a common and a box nail — 0.162 in against 0.135 in at 16d — is not a detail. The full set of trade patterns is really four decisions made independently: how thick the wire is, how the head is formed, how long it is, and what it is coated with. Sinkers are the interesting case because they break the pattern on two axes at once, running both thinner and physically shorter than their penny size claims — a 16d sinker measures 3 1/4 in, and a crew that switched from hand nailing to coated sinkers has quietly changed the penetration on every plate connection in the building. Finish and casing nails abandon the argument entirely: their heads are made to disappear under filler, and they hold trim in place while glue, gravity or a screw does the actual work.
Because nails are specified by the piece and sold by the pound, the last step is a weight conversion nobody enjoys doing at the counter, and it is the one this page does for you. Where the fastener has to come out again, or where the joint needs clamping force rather than shear resistance, the answer is a threaded fastener instead — the screw size chart covers gauge and pilot holes. The page people usually have open at the same time as this one is the plywood calculator, because sheathing quantity and sheathing nailing are worked out together — and where a nailing schedule is printed in the code your jurisdiction adopted, that schedule outranks any chart, this one included.