A chart of knitting needle sizes in millimeters and their corresponding codes used in the US, UK, and Canada.
If you are not sure what size needle should be used for your yarn, this rule of thumb may help: choose needle diameter that is twice the diameter of your yarn.
| Metric, mm | US Standard | UK & Canada Standard |
|---|---|---|
| 1.5 | 0 | – |
| 1.75 | 0 | – |
| 2 | 0 | 14 |
| 2.25 | 1 | 13 |
| 2.5 | – | – |
| 2.75 | 2 | 12 |
| 3 | – | 11 |
| 3.25 | 3 | 10 |
| 3.5 | 4 | – |
| 3.75 | 5 | 9 |
| 4 | 6 | 8 |
| 4.25 | – | – |
| 4.5 | 7 | 7 |
| 4.75 | 8 | 6 |
| 5 | 8 | 6 |
| 5.5 | 9 | 5 |
| 6 | 10 | 4 |
| 6.5 | 10 1/2 | 3 |
| 7 | – | 2 |
| 7.5 | – | 1 |
| 8 | 11 | 0 |
| 9 | 13 | 0 |
| 10 | 15 | 0 |
| 12 | 17 | – |
| 16 | 19 | – |
| 19 | 35 | – |
| 25 | 50 | – |