Here you will find needle size & yarn conversion charts.
As yarns tend to differ from country to country I would advise you always do a tension square if you are in doubt.
| UK | AUSTRALIAN | US | TENSION (over 10x10cm Square) |
| 4ply | 4ply | Fingering/Sport | 28sts x 36rows on 3.25mm |
| Double Knit (DK) | 8ply | Light Worsted | 22sts x 30rows on 4mm |
| Aran | 10ply | Worsted | 18sts x 24rows on 5mm |
| Chunky | 20ply | Bulky | 15sts x 20rows on 6mm |
NEEDLE COVERSION CHART
| IMPERIAL | METRIC | US |
| 13 | 2.25mm | 1 |
| 12 | 2.75mm | 2 |
| 11 | 3mm | |
| 10 | 3.25mm | 3 |
| 9 | 3.75mm | 5 |
| 8 | 4mm | 6 |
| 7 | 4.5mm | 7 |
| 6 | 5mm | 8 |
| 5 | 5.5mm | 9 |
| 4 | 6mm |
10 |