Nominal inches to millimeters
Type a value in nominal to get it in mm instantly.
139.7mm
That's 1.57× as wide as a 4×4 post, while a 2×10 joist’s depth is 1.68× wider.
Convert the other way: mm to nominal
What it means
How big is that board really?
Dry, surfaced softwood dimensions (PS 20). Convert each dimension separately: a 2×6 is 1½ by 5½ in. Hardwoods and rough-sawn lumber differ.
The math
How to convert nominal to mm
Up to 6 in nominal, actual = nominal − ½ in; from 8 in, actual = nominal − ¾ in.
Example: 6 nominal = 139.7 mm.
Every unit
That dimension in every unit
Tables
nominal to mm conversion table
| nominal | mm |
|---|---|
| 1 nominal | 19.05 mm |
| 2 nominal | 38.1 mm |
| 3 nominal | 63.5 mm |
| 4 nominal | 88.9 mm |
| 5 nominal | 114.3 mm |
| 6 nominal | 139.7 mm |
| 8 nominal | 184.15 mm |
| 10 nominal | 234.95 mm |
| 12 nominal | 285.75 mm |
| 14 nominal | 336.55 mm |
| 16 nominal | 387.35 mm |
mm to nominal conversion table
| mm | nominal |
|---|---|
| 38.1 mm | 2 nominal |
| 63.5 mm | 3 nominal |
| 88.9 mm | 4 nominal |
| 114 mm | 5 nominal |
| 140 mm | 6 nominal |
| 184 mm | 8 nominal |
| 235 mm | 10 nominal |
| 286 mm | 12 nominal |
| 337 mm | 14 nominal |
| 387 mm | 16 nominal |
Quick answers
Quick answers
- How many mm is 1 nominal?
- 1 nominal is 19.05 mm.
- How many mm is 10 nominal?
- 10 nominal is 234.95 mm.
- How many mm is 6 nominal?
- 6 nominal is 139.7 mm.
The units
About these units
Nominal inches (nominal)
The name of the dimension: the 4 in 2×4.
Millimeters (mm)
The real dimension in millimeters.
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