Reference charts
Hooks and yarn weights, at a glance.
Two charts worth keeping handy: hook size conversions between millimeters, US letters, and old UK sizing, plus the standard yarn weight categories. Print this page and tape it inside your project bag.
Crochet hook sizes
Millimeters are the most reliable measure; the letter and number systems vary a little between manufacturers. A blank cell means there is no standard equivalent in that system.
| Metric (mm) | US size | UK (old) size |
|---|---|---|
| 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 |
| 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 | · |
| 16.0 mm | Q | · |
| 19.0 mm | S | · |
Yarn weight categories
The Craft Yarn Council numbers you see on yarn labels, 0 through 7. HookPlan uses these same categories in your yarn stash.
| No. | Name | Typical items | Recommended hooks |
|---|---|---|---|
| 0 | Lace | Doilies, lace shawls, delicate edgings | Steel hooks up to 2.25 mm (B-1) |
| 1 | Super Fine | Socks, baby garments, lightweight shawls | 2.25–3.5 mm (B-1 to E-4) |
| 2 | Fine | Baby blankets, light garments, amigurumi with fine detail | 3.5–4.5 mm (E-4 to 7) |
| 3 | Light | Garments, lightweight scarves, summer tops | 4.5–5.5 mm (7 to I-9) |
| 4 | Medium | Blankets, hats, scarves, mittens, most amigurumi | 5.5–6.5 mm (I-9 to K-10.5) |
| 5 | Bulky | Rugs, jackets, quick blankets, winter hats | 6.5–9 mm (K-10.5 to M/N-13) |
| 6 | Super Bulky | Heavy blankets, thick cowls, statement scarves | 9–16 mm (M/N-13 to Q) |
| 7 | Jumbo | Arm-crocheted blankets, jumbo baskets, floor poufs | 16 mm (Q) and larger |