Hook Sizes: US and UK terns
As with everything in crochet, there are multiple terms. For hook sizes, we outdo ourselves as there is 3 ways to denote a hook size – a metric millimetre sizing, a US letter (sometimes a number) or a UK number.
(There are actually 4 types if you include Japanese sizes which are different again but I haven’t included that here for fear of information overload!)
I always stick to the metric mm sizing in my patterns. In a lot of modern western patterns you will be likely to just see the metric and or US sizes but there are still a lot of vintage UK patterns floating around so it’s useful to be aware of the options.
Here’s the table to help you translate!
Recommended hook size by yarn weight
Standard information about yarn weights in the US can be found here. It’s worth noting though that outside the US, different terms are used for similar yarn weights. Below is a table with suggested hook sizes for each of the main yarn weights. However, there is no global standard because so much depends on the pattern you are working.
On top of that, weights can vary even within categories, so please use the below as a guide only and remember that gauge is more important than hook size!!
I have created this chart based on my experience and the range of hooks for Light and Medium weight yarns differs from the Yarn Craft Council.
IUltimately, experience will help you determine what size hook works best for you and the pattern you’re working, but in the meantime make a gauge swatch!