Crochet Hook Size Guide Chart of Metric vs US / UK / Canada Crochet Hook Sizes*:
| 2.0 mm | — | 14 |
| 2.25 mm | B-1 | 13 |
| 2.5 mm | — | 12 |
| 2.75 mm | C-2 | — |
| 3.0 mm | — | 11 |
| 3.25 mm | D-3 | 10 |
| 3.5 mm | E-4 | 9 |
| 3.75 mm | F-5 | — |
| 4.0 mm | G-6 | 8 |
| 4.5 mm | 7 | 7 |
| 5.0 mm | H-8 | 6 |
| 5.5 mm | I-9 | 5 |
| 6.0 mm | J-10 | 4 |
| 6.5 mm | K-10.5 | 3 |
| 7.0 mm | — | 2 |
| 7.5 mm | — | 1 |
| 8.0 mm | L-11 | 0 |
| 9.0 mm | M-13 | 00 |
| 10.0 mm | N-15 | 000 |
| 12 mm | O-16 | — |
| 15.0 mm | P/Q-19 | — |
| 15.75 / 16.0 mm | Q | — |
| 17.5 mm | R | — |
| 19.0 mm | S-35 | — |
| 25.0 mm | U | — |
*Trust the millimeter (mm) size as the letter / number can vary by manufacturer.
