So you have a fantastic ball of yarn that you bought someplace very special and you want to crochet that perfect project with it.
Here's the Problem
But when you look at the label all it shows is a box or a couple of boxes with arrows and numbers and maybe a grid and possibly a pair of knitting needles. There are no crochet hooks to be found. Lets figure out how to convert those knitting needles and numbers into crochet hook letters.
The fastest and easiest place to start is with the pair of knitting needles. On the label near the needles there is usually a number with "US" and a number with "mm."" These numbers coincide with the size of knitting needle recommended for this yarn. The number with the "US" is the size needle in US (United States) terms. The number with the "mm" is the size needle in millimeters or metric terms. Once you know these numbers it's actually a lot easier than you think. All you need is a conversion chart.
On a conversion chart you can look up the knitting needle size recommended on the yarn and on the same line it will have the size of crochet hook that it corresponds to.
In general, the metric size of knitting needle will correspond with the metric size of crochet hook. To make sure you have chosen the correct size of crochet hook, you would want to make a gauge swatch. The recommended gauge is usually found at the beginning of a crochet pattern.
Another Helpful Tip
A yarn weights guide is a more detailed chart for matching hook sizes to yarn weights. It provides the recommended gauge and crochet hook size for each weight yarn. Check it out here: Yarn Weight Standards Guide.
Suzanne, the Crochet Doctor
Do you have a crochet question for me? Ask it in the comments below or contact me here.