Reference / Reference
Hook sizes and yarn weights
Yarn weight classes (US system)
| # | Name | Typical use | Suggested hook |
|---|---|---|---|
| 0 | Lace | doilies, thread crochet | 1.5-2.25 mm steel |
| 1 | Super fine / fingering | socks, fine shawls | 2.25-3.5 mm |
| 2 | Fine / sport | baby items | 3.5-4.5 mm |
| 3 | Light / DK | garments, amigurumi | 4.5-5.5 mm |
| 4 | Medium / worsted | blankets, most amigurumi | 5.5-6.5 mm |
| 5 | Bulky | quick blankets, chenille toys | 6.5-9 mm |
| 6 | Super bulky | chunky blankets | 9-15 mm |
| 7 | Jumbo | arm knitting territory | 15 mm + |
For amigurumi, go 1-2 sizes SMALLER than the suggestion so the stuffing does not show through: worsted with a 3.5-4 mm hook is the common pairing.
Hook letters to millimeters (US)
B=2.25, C=2.75, D=3.25, E=3.5, F=3.75, G=4.0, H=5.0, I=5.5, J=6.0, K=6.5, L=8.0, M/N=9.0, N/P=10.0. Millimeters are the truth; letters drift between brands. Antique patterns cite defunct systems entirely; when modernizing one, swatch to the fabric in the photo instead of chasing the number.