Knitting needle / crochet hook size conversion chart
| mm | UK | US | crochet |
|---|---|---|---|
| 2.0 mm | 14 | 0 | |
| 2.25 mm | 13 | 1 | B |
| 2.5 mm | 12 | - | |
| 2.75 mm | 12 | 2 | C |
| 3.0 mm | 11 | 3 | |
| 3.25 mm | 10 | 3 | D |
| 3.5 mm | 9 | 4 | E |
| 3.75 mm | 9 | 5 | F |
| 4.0 mm | 8 | 6 | G |
| 4.5 mm | 7 | 7 | |
| 5.0 mm | 6 | 8 | H |
| 5.5 mm | 5 | 9 | I |
| 6.0 mm | 4 | 10 | J |
| 6.5 mm | 3 | 10 1/2 | K |
| 7.0 mm | 2 | - | |
| 7.5 mm | 1 | - | |
| 8.0 mm | 0 | 11 | L |
| 9.0 mm | 00 | 13 | |
| 10.0 mm | 000 | 15 | |
| 12.0 mm | 17 | ||
| 15.0 mm | 19 | ||
| 20.0 mm | 35 | ||
| 50.0 mm | 50 |

