crochet hook sizes

Crochet Hook Sizes: A Helpful Guide And Chart For Beginners

Crochet looks like such a fun hobby, and you want to give it a try. You’re excited to pick up a hook and make granny squares and Afghan blankets. But when you get to the craft aisle, you’re shocked by all of the different crochet hook sizes.

With so many choices, how do you know which one to get?

This guide will help answer all of your questions. We’ll explain why it’s important to pick the right size hook and provide a helpful crochet hook size chart so you can confidently select the correct one.

Table Of Contents

An Overview Of Crochet Hook Sizes

Several crochet hook sizes

Crochet hooks have five main parts: the head, throat, shaft, grip, and handle. The diameter of the shaft (the part between the grip and the head) is measured when determining the size. This measurement is taken in millimeters.

While some countries refer to the crochet hook sizes in terms of this measurement, the United States and the United Kingdom do not. Both of these countries have a unique system for naming and numbering hook sizes.

At least, the United Kingdom did have one. Today, it primarily uses the European Union’s preference for using metric sizes to distinguish one crochet hook from another. However, some patterns and hooks are still marked with the older UK system, so it’s still worth learning.

Most modern crochet hooks are marked with a metric measurement and a letter and number combination. This combination is how the US labels each hook. The closer the letter is to A, the smaller the hook. For example, a 2.25 mm hook is called a B/1.

In the United Kingdom, that same hook would be called a 13. In that system, the smaller the number, the bigger the hook.

As you can imagine, these different naming systems can cause confusion. Especially when you add steel crochet hooks into the equation. Those tiny hooks have a labeling system all their own, which we’ll explain later.

What Happens If You Use The Wrong Size?

When you first learn to crochet, you may not have a complete set of crochet hooks with all the sizes. And that’s OK. However, you’ll want to make sure you select patterns and yarn that work with the size crochet hook you do have.

Crocheting with the wrong hook size can produce disastrous results.

Too Large

If your hook is too large, your stitching will be loose and lack definition. It’ll be floppy, and you might notice some holes in the fabric where you can't pull the yarn tight enough.

Too Small

On the other hand, if your hook is too small, you’ll find it difficult to push it through the fabric and pull the yarn tight when creating a stitch. Your stitching will be tight and dense, making the final product stiff and rigid.

How To Pick The Right Size

Crochet hook in action

To improve your chances of success, you need to work with a hook that matches your yarn. Thankfully, you can find this information in a few different places:

  • On the label of your yarn
  • Your yarn company’s website (at GANXXET, you can find this information in the Overview section on individual product pages)
  • At the beginning of your pattern

Once you know what size you need, you can start crocheting.

Crochet Hook Size Chart

But what if you don’t see both measurements on your crochet hook? Is there a simple way to tell what size hook you need?

The answer is yes! You can use a crochet hook size chart.

Here’s one that shows the conversion between metric, US, and UK measurements. That way, no matter what country you live in, you can look up the right size.

Please note that these numbers aren’t standardized. That’s why you may see slightly different numbers or letters from one size chart to another.

Metric Size US Label UK Label
2 mm 14
2.25 mm B-1 13
2.5 mm 12
2.75 mm C-2
3 mm 11
3.125 mm D
3.25 mm D-3 10
3.5 mm E-4 9
3.75 mm F-5
4 mm G-6 8
4.5 mm 7 7
5 mm H-8 6
5.50 mm I-9 5
6 mm J-10 4
6.50 mm K-10 1/2 3
7 mm 2
8 mm L-11
9 mm M/N-13
10 mm N/P-15
11.50 mm P-16
15 mm P/Q
15.75 mm Q
16 mm Q
19 mm S
25 mm T/U/X
30 mm T/X

Steel Crochet Hook Size Chart

Earlier, we mentioned that steel crochet hooks have their own sizing process. These smaller hooks are used for crochet thread or lightweight yarns. On these hooks, the number decreases as the diameter increases.

Here are some of the most common steel sizes:

Metric  US Label
2.7mm 00
2.55mm 0
2.35mm 1
2.25mm 2
2.10mm 3
2mm 4
1.90mm 5
1.80mm 6

How To Choose Yarn For Different Crochet Hook Sizes

Crochet hooks and a crochet heart

If you’re unsure what yarn to use with a certain size crochet hook, it’s important to know that the Craft Yarn Council has a Yarn Standard system that many manufacturers use. It classifies yarn by its weight.

Let’s look at which yarn goes with which hooks:

Yarn Weight Suggested US Crochet Size
0/Lace or thread Steel #1 or #2 or B-1
1/Super Fine C-2 or D-3
2/Fine E-4 or F-5
3/Light or Light Worsted G-6, 7, or H-8
4/Medium or Worsted I-9 or J-10
5/Bulky or Chunky L-11 or M/N
6/Super Bulky N/P-15
7/Jumbo  P/Q or Q

If you want to create something with the worsted weight Merino Wool, you’ll select an I-9 or J-10 crochet hook. But if you use the Chunky Art Wool, you’ll need to reach for your larger hook. The P/Q or Q should be a good fit.

To make sure you’ve chosen the right size, it’s a good idea to create a gauge swatch before you begin your project. Then you can compare your swatch to the notes in the pattern and make sure they match.

To do this, crochet a sample square using the crochet stitches from the pattern. When your sample piece is five or six inches high, stop and measure. Count how many stitches are in a four-inch row. Your pattern should tell you what the gauge should be.

If yours is too big or too small, you may need to use a different size hook to get the right spacing.

The Best Yarn For Any Hook

Large size crochet hook with a box of yarn

As we said earlier, crochet hook sizes can be a bit daunting. But, hopefully, you now have a better idea of which hook you need for your project. And if you forget, you can always come back to our crochet hook size chart and see which one will be best.

Now you can pick up some yarn and the right size crochet hook and start creating! Whether you’re making a bookmark or a scarf, GANXXET has the yarn you need for your project. Check out our selection of yarn here.


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