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Crochet hook size chart: mm, US and UK
Crochet hooks are sized in millimetres everywhere; US hooks add a letter and number (a 5 mm hook is an H-8), and old UK hooks use a number that gets smaller as the hook gets bigger (a 5 mm hook is a 6). Pick your yarn below to see which hook to use.
Which hook for my yarn?
Hook sizes
| Millimetres | US | UK (old) |
|---|---|---|
| 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-10½ | 3 |
| 7.0 mm | – | 2 |
| 8.0 mm | L-11 | 0 |
| 9.0 mm | M/N-13 | 00 |
| 10.0 mm | N/P-15 | 000 |
| 11.5 mm | P-16 | – |
| 15.0 mm | P/Q | – |
| 15.75 mm | Q | – |
| 19.0 mm | S | – |
Yarn weights and hooks
| Yarn weight | Hook range | Good for |
|---|---|---|
| 0 Lace | 1.4–2.25 mm | doilies, fine lace |
| 1 Super fine (fingering, sock) | 2.25–3.5 mm | socks, baby things, tiny amigurumi |
| 2 Fine (sport, baby) | 3.5–4.5 mm | baby clothes, light shawls |
| 3 Light (DK) | 4.5–5.5 mm | garments, amigurumi |
| 4 Medium (worsted, aran) | 5.5–6.5 mm | blankets, hats, most amigurumi |
| 5 Bulky (chunky) | 6.5–9 mm | quick blankets, cowls |
| 6 Super bulky | 9–15 mm | chunky blankets, rugs |
| 7 Jumbo | 15–25 mm | arm-knit style blankets |
Questions
What size crochet hook should I use?
Use the hook range on your yarn label. Medium (worsted, weight 4) yarn usually takes a 5.5-6.5 mm (I-9 to K-10½) hook. For amigurumi, go 0.5-1 mm smaller than the label so the stuffing doesn't show.
What is a 5 mm crochet hook in US sizes?
A 5 mm hook is an H-8 in US sizes and a 6 in old UK sizes.
Why do US and UK hook sizes differ?
US hooks use letters and numbers, old UK hooks use a number that gets smaller as the hook gets bigger. Millimetres are the same everywhere, so buy and follow patterns by the mm size.
Sizes follow the Craft Yarn Council's standard labels. Brands vary a little, so always check your gauge or, for toys, that the fabric is tight.
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