See the below image for the Knitting needle sizes and conversion diagram. Knitting Needle Sizes – A Conversion Chart Knitting needle sizes tend to be measure the diameter of the needles and range from 2.0 mm right up to 25.0 mm. Just to make it a bit more complicated, not all countries use the same ‘names’ for needle sizes.
While the US and the UK use the same metric sizes, their numbering systems run in opposite directions. In the US, needle sizes start at 0 and increase to 50. However, in the UK, sizes start at 14 and go up to 000. In Japan, knitting needles use different standard metric sizes, starting at 2.1 mm and going up to 25 mm.
Convert from Metric to US to UK and Canadian sizes for knitting needles. Knitting needles have also been called knitting sticks, knitting pins, knitting wires, or simply wires or rods. Length and thickness of the needles vary depending on the type of yarn used and the type of fabric to be produced.