There are three primary scales on which the size of Knitting needles are measured: the US/American, UK/English, and Metric. The US and Metric scales are by far the most common these days, and so you're only likely to encounter the UK/English scale if you've acquired a set of older needles. Nonetheless, a Needle Gauge is an invaluable tool for measuring needle sizes and performing conversions.
The following table provides conversions between the different scales:
US/American | Metric (mm) | UK/English |
---|---|---|
000 | 1.50 | 15 |
00 | 1.75 | 14 |
0 | 2.00 | 13 |
1 | 2.25 | 12 |
2 | 2.75 | 11 |
3 | 3.25 | 10 |
4 | 3.50 | 9 |
5 | 3.75 | 8 |
6 | 4.00 | 7 |
7 | 4.50 | 6 |
8 | 5.00 | 5 |
9 | 5.50 | 4 |
10 | 6.00 | 3 |
10 1/2 | 6.50 | 2 |
11 | 8.00 | 1 |
13 | 9.00 | 00 |
15 | 10.00 | 000 |
17 | 12.00 | - |