| Needle Size Conversions | Crochet Hook Conversions | |||||
| UK | Metric | USA | UK | Metric | USA | |
| 14 | 2mm | 0 | 14 | 2mm | - | |
| 13 | 2.25mm | 1 | 13 | 2.25mm | B/1 | |
| - | 2.5mm | - | 12 | 2.5mm | - | |
| 12 | 2.75mm | 2 | - | 2.75mm | C/2 | |
| 11 | 3mm | - | 11 | 3mm | - | |
| 10 | 3.25mm | 3 | 10 | 3.25mm | D/3 | |
| - | 3.5mm | 4 | 9 | 3.5mm | E/4 | |
| 9 | 3.75mm | 5 | - | 3.75mm | F/5 | |
| 8 | 4mm | 6 | 8 | 4mm | G/6 | |
| 7 | 4.5mm | 7 | 7 | 4.5mm | 7 | |
| 6 | 5mm | 8 | 6 | 5mm | H/8 | |
| 5 | 5.5mm | 9 | 5 | 5.5mm | I/9 | |
| 4 | 6mm | 10 | 4 | 6mm | J/10 | |
| 3 | 6.5mm | 10.5 | 3 | 6.5mm | K/10½ | |
| 2 | 7mm | - | 2 | 7mm | - | |
| 1 | 7.5mm | - | 0 | 8mm | L/11 | |
| 0 | 8mm | 11 | 0 | 9mm | M/13 | |
| 0 | 9mm | 13 | 0 | 10mm | N/15 | |
| 0 | 10mm | 15 | - | 11.5mm | P/16 | |
| - | 12mm | 17 | - | 16mm | Q | |
| - | 15mm | 19 | - | 19mm | S | |
| - | 20mm | 36 | ||||
| - | 25mm | 50 | ||||
| Yarn Conversions | |
| UK | USA |
| 1 Ply | Laceweight |
| 2 Ply | Fingering |
| 3 Ply | Sock |
| 4 Ply | Sport |
| Double Knit | DK/Light Worsted |
| Aran | Worsted |
| Chunky | Bulky |
| Super Chunky | Super Bulky |