My favorite crochet hooks are Clover aluminums and Hamanaka hooks. I am constantly double checking the conversion between Japan and US crochet hook sizing. I finally broke down and made a chart for myself. And, now you can use it too!
No Standard Measuring System
There weren’t any standards available in the crochet hook making industry for decades. And, for reasons I don’t know, once the patterns and hooks started being published in the US, there was more changed than just the UK stitch names. We started using letters instead of numbers.
Duplicate Crochet Hook Sizes
Since there were no standards, different companies used different sizes for different letters. Maybe the machines weren’t calibrated correctly. Maybe there was a mistake. Maybe a hook was made in one size but it was changed later. I honestly have no clue how all of that happened or even why it happened.
Notice and Disclaimer: All crochet patterns written by Kim Guzman at CrochetKim are in US terms. All photos not copyright to Kim Guzman are posted with permission. This website contains affiliate links.
When there are duplicates, I’ve listed the duplicates in the chart. Crochet hooks in the US these days, though, are fairly standard and, when you get a hook in a specific size, it’s usually the same across all brands.
If you have one of the random millimeter sizes not listed in the chart, that’s great! When you’re trying to get the same tension/gauge as the designer, sometimes it’s helpful to have all resources available to you and that includes having lots of different hook sizes.
Australia and UK Crochet Hook Sizes
If you’re in Australia or the UK, you’ll probably find your hooks in millimeter sizing. You just follow the chart to see what US or Japanese equivalent you would need.
Japanese Crochet Hook Sizes
These are the pretty Hamanaka crochet hooks. As with many Japanese hooks, they have a completely different numbering system.
Since I use these hooks most of the time, I find myself double checking the numbers and letters constantly when I’m writing patterns.
Writing Crochet Patterns
For my own patterns, I tend to always write out the the millimeter and US sizing to help no matter where you live. If you start using millimeters, you’ll usually never have a problem….. except the Japanese hooks, of course. Leave it to me to be different. ha!