How to Understand Crochet Thread Sizes

Should you start a crochet thread project? Here’s our guide to crochet thread sizes.

Have you always worked with yarn for your crochet projects but would like to expand to thread? I’ve often considered working with crochet thread myself, but it can be daunting at first.

What size should I use for which type of projects? What type of crochet hook? Is it difficult to learn to crochet with thread? So the reasonable starting point is understanding crochet thread sizes.


Understanding Crochet Thread Sizes

If you’re already familiar with yarn, then you know that it is identified by a number that corresponds to the yarn’s weight. Crochet thread works similarly.

Crochet thread sizes are identified by assigning larger numbers to smaller threads and smaller numbers to larger threads, which is the opposite of how yarn identification numbers work. It does take a bit to get used to this method of identifying crochet thread sizes, but you’ll get there.

The sizing for crochet thread begins at 3 and goes all the way to size 100. That is quite a range!

So the largest crochet size is a 3 and the smallest is a 100.

crochet thread sizes

Choosing the Correct Crochet Thread Sizes

Crochet thread comes in a variety of sizes depending on where you buy thread from, but you can certainly begin with some of the common crochet thread sizes as you begin to learn how to crochet with thread.

A good size, to begin with, is crochet thread sizes 3 or 5 because they are slightly thinner than a lightweight crochet yarn. Working with these sizes will ease you into using smaller threads.

You can crochet scarves, shawls, amigurumi, and baby dresses using this size.

Size 10 is just a touch thinner and makes wonderful edgings, doilies, jewelry, and more. 10 is one of the most common crochet thread sizes.

Another common crochet thread size is 20, used frequently for edging, bedspreads, and curtains.

Skip to size 80 and you find yourself working with a very fine crochet thread, often used in “tatting.” The finest designs will often be worked using crochet thread sizes 80 or smaller.

crochet thread sizes

Finding the Best Crochet Hook for Crochet Thread Sizes

When I first began to crochet and bought a “beginner’s kit,” it contained several steel and aluminum crochet hooks. The aluminum hooks I have used from the very beginning, but those steel hooks always frightened me. They were so small they certainly wouldn’t work with regular yarn!

Eventually, I discovered they were for those lacy doilies my great-aunts made and the pretty edging on my baby blanket. I also discovered crochet thread was meant to be used with those shiny steel hooks.

Assuming you’re already familiar with yarn crochet, then you’re aware that aluminum crochet hooks are designated by letter assignments. Well, with steel crochet hooks you will look for numbers instead. Additionally, steel crochet hooks are identified by two numbers. I know, right?

You’ve got this though. Again, the crochet hooks that correspond with crochet thread are identified similarly to the thread. The larger the size number means the smaller the hook. In other words, a size 12 hook is larger than the size 16 hook.

Fortunately, that second number I mentioned? It is in mm, which makes it easy to tell which hook is larger and which hook is smaller!

Last, but not least, when you are working from a pattern, that is a great starting place to figure out which size hook will work best! You may need to adjust up or down a bit for the gauge if needed, but it’s a start!

For even more information, check out this comprehensive guide to crochet thread!

crochet thread sizes

Also see: Difference Between Knitting vs Crocheting

You now have a better understanding of crochet thread sizes.

Now what? Now that you already know about crochet thread, it is time to start making crochet thread projects.

Head over to our sister site for patterns to use your newfound knowledge! Enjoy working with crochet thread. If you are a beginner, an easy way to get started is with a crochet set

Let us know if you love it and share your works on our Facebook Page.

Find craft-related tutorials here.