Whats is the mm equivalent of US / old UK knitting needles? When converting from US or old UK knitting needle sizes to mm, what are the conversions for these?
Here's an overview of all the knitting needle sizes I know.


Metric    UK        US
0.5mm     24        -
0.75mm    22        -
1.0mm     20        5/0
1.25mm    18        4/0
1.5mm     17        000
1.625mm   16        -
1.75mm    15        00
2.0mm     14        0
2.25mm    13        1
2.5mm     -         1.5
2.75mm    12        2
3.0mm     11        2.5
3.25mm    10        3
3.5mm     -         4
3.75mm    9         5
4.0mm     8         6
4.5mm     7         7
5.0mm     6         8
5.5mm     5         9
6.0mm     4         10
6.5mm     3         10.5
7.0mm     2         -
7.5mm     1         -
8.0mm     0         11
9.0mm     00        13
10.0mm    000       15
12.0mm    -         17
15.0mm    -         19
20.0mm    -         35
50.0mm    -         50


For crochet hooks, see: What is the conversion for UK and US crochet hooks to mm?