A 7mm crochet hook has no single standard US letter (between a K-10.5 (6.5mm) and an L-11 (8mm), no standard US letter). I keep the mm number as my main reference for this size, since letter labeling is where most of the confusion happens between brands.
7mm to US letter, UK, and yarn weight
A 7mm crochet hook has no single standard US letter (between a K-10.5 (6.5mm) and an L-11 (8mm), no standard US letter). It’s typically used for bulky weight yarn, and I check the mm stamp on the hook itself whenever a pattern’s letter doesn’t match what I expect.
What projects use a 7mm hook
Match bulky weight yarn to this hook for the gauge most patterns expect, then adjust up or down a size if your own tension runs tight or loose. I always swatch first for anything that needs to fit.
Frequently asked questions
Is 7mm the same as a lettered size?
A 7mm crochet hook has no single standard US letter (between a K-10.5 (6.5mm) and an L-11 (8mm), no standard US letter).
What size yarn goes with a 7mm hook?
Bulky weight yarn is the usual match for this size.
See the full hook size chart
Compare 7mm against every other mm, US, and UK size in one table.