Japanese sizes to millimeters
Type a value in JP to get it in mm instantly.
3.9mm
That's 1.42× as thick as the needle for sock yarn, while the needle for DK yarn is 1.03× thicker.
Convert the other way: mm to JP
What it means
Which yarn suits that needle?
Typical needle sizes for each yarn weight; the ball band and your tension swatch have the final word.
The math
How to convert JP to mm
US and UK sizes are tables: US 6 = UK 8 = 4 mm, US 8 = UK 6 = 5 mm. Japanese size n is 2.1 + 0.3 × n mm.
Example: 6 JP = 3.9 mm.
Every unit
That needle in every system
Tables
JP to mm conversion table
| JP | mm |
|---|---|
| 0.5 JP | 2.25 mm |
| 2.17 JP | 2.751 mm |
| 3.83 JP | 3.249 mm |
| 4.67 JP | 3.501 mm |
| 5.5 JP | 3.75 mm |
| 6.33 JP | 3.999 mm |
| 8 JP | 4.5 mm |
| 9.67 JP | 5.001 mm |
| 11.3 JP | 5.49 mm |
| 13 JP | 6 mm |
| 14.7 JP | 6.51 mm |
mm to JP conversion table
| mm | JP |
|---|---|
| 2.25 mm | 0.5 JP |
| 2.75 mm | 2.16667 JP |
| 3.25 mm | 3.83333 JP |
| 3.5 mm | 4.66667 JP |
| 3.75 mm | 5.5 JP |
| 4 mm | 6.33333 JP |
| 4.5 mm | 8 JP |
| 5 mm | 9.66667 JP |
| 5.5 mm | 11.3333 JP |
| 6 mm | 13 JP |
| 6.5 mm | 14.6667 JP |
Quick answers
Quick answers
- How many mm is 1 JP?
- 1 JP is 2.4 mm.
- How many mm is 10 JP?
- 10 JP is 5.1 mm.
- How many mm is 6 JP?
- 6 JP is 3.9 mm.
The units
About these units
Japanese sizes (JP)
2.1 mm plus 0.3 mm per size.
Millimeters (mm)
The metric size: the needle’s diameter.
Keep going