Sources and method
Sources
US sizes and yarn weights: Craft Yarn Council standards. Old UK/Canadian sizes from the usual conversion charts. Japanese knitting needles (棒針) run 0号 = 2.1 mm, then 0.3 mm per number; Japanese crochet hooks use their own n/0 scale. Sizes marked with no equivalent have none in that system.
Corrections
Found a mistake? Write to contact@niftyant.com.