Nail & Screw Size Chart — Penny Sizes, Wood Screw Gauges & Pilot Holes
Nail penny sizes 2d–60d with lengths and common/box shank diameters per FPL and NDS tables, plus wood screw gauges #2–#14 with pilot hole sizes.
Updated August 18, 2026
Nail sizes are still quoted in the medieval English "penny" system, written d (for denarius): a 2d nail is 1 inch long and each step up the scale adds length until 60d reaches 6 inches. The penny number fixes the length; the diameter then depends on the pattern. Common nails carry the full structural shank — a 16d common is 3-1/2 in × 0.162 in, the nail framing tables assume — while box nails share the same lengths on visibly thinner shanks (a 16d box is only 0.135 in) that resist splitting in thin or brittle stock but hold correspondingly less.
Wood screws use a gauge number that encodes the major (outside thread) diameter through the formula D = 0.060 + 0.013 × gauge, so a #8 is 0.164 in and a #10 is 0.190 in — the diameter column below is computed from that formula, which published tables reproduce exactly. The pilot-hole columns give the two-chart consensus drilling sizes: hardwood takes a slightly larger pilot than softwood because dense stock splits rather than compresses, the same reasoning behind the FPL Wood Handbook lead-hole rule of roughly 70% of the thread root diameter in softwood and 90% in hardwood.
Nail Penny Sizes 2d–60d — Common & Box
| Penny | Length (in) | Length (mm) | Common Ø (in) | Box Ø (in) |
|---|---|---|---|---|
| 2d | 1 | 25.4 | 0.072 | — |
| 3d | 1-1/4 | 31.8 | 0.080 | 0.076 |
| 4d | 1-1/2 | 38.1 | 0.099 | 0.080 |
| 5d | 1-3/4 | 44.4 | 0.099 | 0.080 |
| 6d | 2 | 50.8 | 0.113 | 0.099 |
| 7d | 2-1/4 | 57.1 | 0.113 | 0.099 |
| 8d | 2-1/2 | 63.5 | 0.131 | 0.113 |
| 10d | 3 | 76.2 | 0.148 | 0.128 |
| 12d | 3-1/4 | 82.5 | 0.148 | — |
| 16d | 3-1/2 | 88.9 | 0.162 | 0.135 |
| 20d | 4 | 101.6 | 0.192 | 0.148 |
| 30d | 4-1/2 | 114.3 | 0.207 | — |
| 40d | 5 | 127.0 | 0.225 | — |
| 50d | 5-1/2 | 139.7 | 0.244 | — |
| 60d | 6 | 152.4 | 0.263 | — |
ASTM F1667-pattern sizes per FPL Wood Handbook Tables 7-1/7-2 and NDS 2018 Table L4. Source splits: 60d common prints 0.262 (FPL) vs 0.263 (NDS, shown); 6d/7d box print 0.098 (FPL) vs 0.099 (NDS, shown). Box sizes without a two-source published value (2d, 9d, 12d, 30d–60d) are omitted, not estimated. mm = 25.4 × in.
Wood Screw Gauges #2–#14 — Major Diameter & Pilot Holes
| Gauge | Major Ø (in) | Major Ø (mm) | Pilot — softwood | Pilot — hardwood |
|---|---|---|---|---|
| #2 | 0.086 | 2.18 | 1/16″ | 1/16″ |
| #3 | 0.099 | 2.51 | 1/16″ | 5/64″ |
| #4 | 0.112 | 2.84 | 1/16″ | 5/64″ |
| #5 | 0.125 | 3.17 | 5/64″ | 3/32″ |
| #6 | 0.138 | 3.51 | 3/32″ | 7/64″ |
| #7 | 0.151 | 3.84 | 7/64″ | 7/64″ |
| #8 | 0.164 | 4.17 | 7/64″ | 1/8″ |
| #9 | 0.177 | 4.50 | 1/8″ | 9/64″ |
| #10 | 0.190 | 4.83 | 1/8″ | 9/64″ |
| #11 | 0.203 | 5.16 | — | — |
| #12 | 0.216 | 5.49 | 9/64″ | 5/32″ |
| #14 | 0.242 | 6.15 | 5/32″ | 3/16″ |
Major Ø computed from the ASME B18.6.1 gauge formula 0.060 + 0.013 × gauge (matches FPL Table 7-9). Pilots are the consensus of two published charts; where they split by one drill size the larger (split-safe) size is shown. #11 pilots have no two-source published value and are omitted.
Sources & Further Reading
- FPL Wood Handbook (Forest Products Laboratory), Fastenings chapter — Tables 7-1 (common wire nails), 7-2 (box nails), 7-9 (screw shank diameters), and the 70%/90%-of-root lead-hole guidance
- ANSI/AWC NDS 2018, Table L4 — common and box nail reference dimensions (adjudicated against FPL; NDS values shown where the two split by 0.001 in)
- Pilot holes: consensus of the WorkshopCalc and Misumi USA published pilot-hole charts (independent); screw major diameters computed from the ASME B18.6.1 gauge formula
Frequently Asked Questions
What does the "d" in nail sizes mean?
It abbreviates denarius, the Roman penny — nails were once priced per hundred, so a "sixteen-penny" nail cost 16 pence per 100. Today the penny number simply indexes length: 2d is 1 inch, and the scale runs to 60d at 6 inches. Diameter is set separately by the pattern (common, box, sinker), which is why a 16d box nail is thinner than a 16d common.
What is the difference between common and box nails?
Length for length, box nails are thinner: at 8d both are 2-1/2 in long, but the common shank is 0.131 in versus 0.113 in for box. The thin shank starts fewer splits in dry or thin stock, at the cost of bending more easily and holding less — structural fastening schedules that call out "16d common" mean the full 0.162 in shank, and a box nail is not an equal substitute.
How big should a pilot hole be for a wood screw?
Slightly larger in hardwood than softwood: a #8 screw takes about a 7/64 in pilot in softwood and 1/8 in in hardwood. The FPL rule of thumb behind the charts is a lead hole near 70% of the thread root diameter in softwood and 90% in hardwood — dense wood cannot compress out of the thread’s way, so it splits instead unless more material is removed first.
What diameter is a #8 or #10 wood screw?
Screw gauges follow D = 0.060 + 0.013 × gauge, so a #8 is 0.060 + 0.104 = 0.164 in and a #10 is 0.190 in — just under 3/16 in. The formula is exact for every standard gauge, which is why the diameter column in this chart is computed rather than transcribed.
Try the Calculators
Nail & Screw Size Chart — Penny Sizes, Wood Screw Gauges & Pilot Holes — reuven.tools/reference/nail-screw-sizes — verified against: FPL Wood Handbook (Forest Products Laboratory), Fastenings chapter — Tables 7-1 (common wire nails), 7-2 (box nails), 7-9 (screw shank diameters), and the 70%/90%-of-root lead-hole guidance; ANSI/AWC NDS 2018, Table L4 — common and box nail reference dimensions (adjudicated against FPL; NDS values shown where the two split by 0.001 in); Pilot holes: consensus of the WorkshopCalc and Misumi USA published pilot-hole charts (independent); screw major diameters computed from the ASME B18.6.1 gauge formula