Japanese to Metric (mm) hook sizes
Japanese crochet hook sizes converted to Metric (mm), with a link to the full detail page for every size.
Japanese sizes are not exact equivalents
Japanese 号 (gō) hooks step in their own increments — 4/0号 is 2.5 mm, while the nearest US hook,
C/2, is 2.75 mm. That quarter millimetre changes gauge in amigurumi. Where a Japanese pattern
names a 号 size, buy the millimetre size, not the lettered equivalent.
| Japanese | Metric (mm) | Detail |
|---|---|---|
| レース針14号 | 0.5 mm | 0.5 mm |
| レース針12号 | 0.6 mm | 0.6 mm |
| レース針10号 | 0.75 mm | 0.75 mm |
| レース針8号 | 0.9 mm | 0.9 mm |
| レース針6号 | 1 mm | 1 mm |
| レース針4号 | 1.25 mm | 1.25 mm |
| レース針2号 | 1.5 mm | 1.5 mm |
| レース針0号 | 1.75 mm | 1.75 mm |
| 2/0号 | 2 mm | 2 mm |
| 3/0号 | 2.3 mm | 2.3 mm |
| 4/0号 | 2.5 mm | 2.5 mm |
| 5/0号 | 3 mm | 3 mm |
| 6/0号 | 3.5 mm | 3.5 mm |
| 7/0号 | 4 mm | 4 mm |
| 7.5/0号 | 4.5 mm | 4.5 mm |
| 8/0号 | 5 mm | 5 mm |
| 9/0号 | 5.5 mm | 5.5 mm |
| 10/0号 | 6 mm | 6 mm |
| 7mm | 7 mm | 7 mm |
| 8mm | 8 mm | 8 mm |
Other hook charts
Last updated 2026-08-30.