Yarn sizes, thicknesses, weights
You’d think that with the number of years yarn has been in this household, this chart would have been memorized ages ago. Er. Nope. And no, the smallest yarn sizes listed don’t have gauge or needle listed. This is a general guide, only. Your mileage may vary. And you may decide to break all the rules, and knit fingering weight yarn with size 7 or 8 needles. It’s allowed. Honest. The knitting police would have hauled me in long ago otherwise.
On a related note, if you need help finding a good yarn substitute, check out Yarnsub.