Here is a conversion chart, produced by the Knitting and Crochet Guild:
Crochet hook conversion chart metric/USA | Metric (mm) | USA | 0.60 | 14 | 0.75 | 12 | 1.00 | 10 | 1.25 | 9 | 1.50 | 8 | 1.76 | 7 | 2.00 | B | 2.50 | C | 3.00 | D | 3.50 | E | 4.00 | F | 4.50 | G | 5.00 | H | 5.50 | I | 6.00 | J | 6.50 | | 7.00 | K | | L | 8.00 | M | 9.00 | N | 10.00 | O | 12.00 | P | 15.00 | Q |
| Yarn thickness or weight conversion chart UK/ USA/ Australia /NZ | UK | USA | Australia/NZ | 2 ply | light fingering | | 3 ply | fingering | | 4 ply | fingering / sport | 5 ply | double knitting (DK) | sport / knitting worsted | 8 ply | | knitting worsted | 10 ply | Aran | | 12 ply | Chunky | bulky | 14 ply | No 10 crochet cotton | bedspread weight crochet cotton | |
| Knitting terms conversion chart UK / USA | UK | USA | tension | gauge | stocking stitch | stockinette stitch | cast off | bind off | grafting | Kitchener stitch |
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Crochet terms conversion chart UK/USA | UK | USA | slip stitch | slip stitch | double crochet | single crochet | half treble | half double crochet | treble | double crochet | double treble | treble | triple treble | double treble |
| Needle size conversion chart UK/metric/USA | UK | Metric (mm) | USA | 000 | 10 | 15 | 00 | 9 | 13 | 0 | 8 | 11 | 1 | 7.5 | | 2 | 7 | | 3 | 6.5 | 10.5 | 4 | 6 | 10 | 5 | 5.5 | 9 | 6 | 5 | 8 | 7 | 4.5 | 7 | | | 6 | 8 | 4 | | 9 | 3.75 | 5 | | 3.5 | 4 | 10 | 3.25 | 3 | 11 | 3 | | 12 | 2.75 | 2 | | 2.5 | | 13 | 2.25 | 1 | 14 | 2 | 0 |
| Needle size conversion chart UK/metric | UK | Metric (mm) | 15 | 1.85 | 16 | 1.64 | 18 | 1.23 | 20 | 0.92 | 22 | 0.71 |
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