Why Crochet Hook Size Matters
Hook size directly affects stitch size, fabric density, and the overall appearance of your project. A hook that's too small for a given yarn will create a stiff, inflexible texture. A hook that's too large will create a loose, holey texture. The right combination of hook and yarn is the foundation of a successful project.
Crochet Hook Size Conversion Chart
| Metric (mm) | US Size | UK Size | Recommended Yarn |
|---|---|---|---|
| 1.5 | — | — | Lace |
| 1.75 | — | — | Lace |
| 2.0 | — | 14 | Fingering |
| 2.25 | B/1 | 13 | Fingering |
| 2.5 | — | 12 | Fingering |
| 2.75 | C/2 | — | Fingering / Sport |
| 3.0 | — | 11 | Sport |
| 3.25 | D/3 | 10 | Sport |
| 3.5 | E/4 | 9 | Sport / DK |
| 3.75 | F/5 | — | DK |
| 4.0 | G/6 | 8 | DK / Light Worsted |
| 4.5 | 7 | 7 | DK / Worsted |
| 5.0 | H/8 | 6 | Worsted (Medium) |
| 5.5 | I/9 | 5 | Worsted / Aran |
| 6.0 | J/10 | 4 | Aran / Bulky |
| 6.5 | K/10½ | 3 | Bulky |
| 7.0 | — | 2 | Bulky |
| 8.0 | L/11 | 0 | Super Bulky |
| 9.0 | M-N/13 | 00 | Super Bulky |
| 10.0 | N-P/15 | 000 | Super Bulky / Jumbo |
| 12.0 | P/16 | — | Jumbo |
| 15.0 | P-Q/19 | — | Jumbo |
| 20.0 | S/36 | — | Jumbo / Roving |
How to Choose the Right Hook for Your Yarn
The most reliable method is to check the yarn label — most yarns indicate the recommended hook size (and needles). If you don't have the label, follow the yarn weight and the chart above.
For crocheting amigurumi, choose a hook 1–2 sizes smaller than the yarn recommends — you need a denser fabric so the stuffing doesn't show through.
For openwork and lace patterns, try a hook 1 size larger — stitches will be more airy and the pattern will show better.
Crochet Hook Materials
Aluminum — most common, lightweight, smooth surface. Yarn glides well. Affordable. Ideal for beginners.
Bamboo/Wood — lighter than metal, warmer to the touch. Yarn slides less — good for slippery yarn (silk, satin). May wear down over time.
Plastic — cheapest, lightweight, but less precise. Suitable for larger sizes (8mm+) where a metal hook would be heavy.
Ergonomic — hooks with rubber grip or shaped handles. Reduce hand fatigue during extended crocheting. Recommended for those who crochet for hours daily.
Tunisian hooks — long (30+ cm) with straight shaft and stopper at the end. Specifically for Tunisian crochet. Cable versions also exist for wide projects.
US vs. UK System
Beware of confusion — the US and UK numbering systems are opposite. In the US system, higher letter/number = larger hook (B is small, S is large). In the UK system, higher number = smaller hook (14 is small, 2 is large). Therefore, it's safest to use millimeters — they are universal and unambiguous.
