Old UK and Canadian sizes to millimeters
Type a value in UK to get it in mm instantly.
5mm
That's about the same as the needle for worsted yarn.
Convert the other way: mm to UK
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 UK 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 UK = 5 mm.
Every unit
That needle in every system
Tables
UK to mm conversion table
| UK | mm |
|---|---|
| 0 UK | 8 mm |
| 3 UK | 6.5 mm |
| 4 UK | 6 mm |
| 5 UK | 5.5 mm |
| 6 UK | 5 mm |
| 7 UK | 4.5 mm |
| 8 UK | 4 mm |
| 9 UK | 3.75 mm |
| 9.5 UK | 3.5 mm |
| 10 UK | 3.25 mm |
| 12 UK | 2.75 mm |
| 13 UK | 2.25 mm |
| 14 UK | 2 mm |
mm to UK conversion table
| mm | UK |
|---|---|
| 2 mm | 14 UK |
| 2.25 mm | 13 UK |
| 2.75 mm | 12 UK |
| 3.25 mm | 10 UK |
| 3.5 mm | 9.5 UK |
| 3.75 mm | 9 UK |
| 4 mm | 8 UK |
| 4.5 mm | 7 UK |
| 5 mm | 6 UK |
| 5.5 mm | 5 UK |
| 6 mm | 4 UK |
| 6.5 mm | 3 UK |
| 8 mm | 0 UK |
Quick answers
Quick answers
- How many mm is 1 UK?
- 1 UK is 7.5 mm.
- How many mm is 10 UK?
- 10 UK is 3.25 mm.
- How many mm is 6 UK?
- 6 UK is 5 mm.
The units
About these units
Old UK and Canadian sizes (UK)
Wire-gauge numbers that fall as the needle grows.
Millimeters (mm)
The metric size: the needle’s diameter.
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