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Crochet Hook Sizes and Conversion Chart

Crochet hooks come in a variety of types and sizes. When you first start crochet, you may wonder about the many ways that crochet hook sizes are labeled.

In this post, I will explain the different ways that crochet hooks are labeled and give you handy size conversion charts, so you’ll always know what size crochet hook to use.

a variety of aluminum crochet hooks with a skein of pink yarn in the background

What Are All The Sizes Of Crochet Hooks?

Have you ever read a crochet pattern and thought, “why is this crochet hook labeled with three different sizes?”

I’ve been there – crochet hook sizing can be confusing at first! You see, crochet hook size labeling varies by country and by region

For example, the US uses a system of letters and numbers. The UK and Canada use a different numbering system, and other countries like Australia and New Zealand use metric sizes. 

Crochet Hook Sizes 

The size of a crochet hook is determined by the diameter of its shaft. The size of the shaft determines the size of the yarn loops in the crochet fabric.

And as we just discussed, different manufacturers label their crochet hooks with varying systems of measurement.

These days, the good news is that most crochet hook manufacturers label their hooks with both numbers or letters AND metric sizing.  

You can use the crochet hook size charts below to help you convert one measurement system to another.

For example, if you have a crochet hook that says 4mm, you can look at the conversion charts and know that it’s also called a G/6 hook in the US or a size 8 hook in the UK.

Regular Crochet Hook Size Chart

The following size chart shows standard crochet hooks – the kind made from aluminum, wood, or plastic. These are the types of crochet hooks you use with yarn – from sock yarn to super-bulky wool.

In the US, you will find that the higher the number, the larger the hook. For more information, check out the size standards set out by Craft Yarn Council.

MetricUSUKJapan
2 mm0142/0
2.25 mmB-1133/0
2.50 mm4/0
2.75 mmC-212
3 mm115/0
3.25 mmD-310
3.50 mmE-46/0
3.75 mmF-59
4 mmG-68
4.25 mmG Boye
4.50 mm777/0
4.75
5 mmH-868/0
5.50 mmI-959/0
6 mmJ-10410/0
6.50 mmK- 10 1/23
7 mm2
7.5 mm1
8 mmL-110
9 mmM/N-1300
10 mmN/P-15000
15 mmP/Q
16 mmQ
19 mmS
25 mmT/U/X

Note: Since letter and number sizing can vary by brand and region, you can always rely on the metric (mm/millimeter) sizing for an accurate measurement. 

Steel Crochet Hook Size Chart

The chart below shows steel crochet hooks, which are the type of hooks you use with crochet thread or lace-weight yarn. These steel hooks have a different numbering system than regular hooks. 

In the US, you will find that the higher the number, the smaller the hook. (This is the reverse of regular hook sizing.) 

MetricUSUK
3.50 mm00
3.25 mm00
2.75 mm11
2.25 mm21 1/2
2.1 mm32
2 mm42 1/2
1.9 mm53
1.8 mm63 1/2
1.65 mm74
1.5 mm84 1/2
1.4 mm95
1.3 mm105 1/2
1.1 mm116
1 mm126 1/2
0.85 mm137
0.75 mm14

Choosing the Right Size Crochet Hook

Now that you know how different sizes of crochet hooks are labeled, you may be wondering:

How Do You Know What Size Crochet Hook To Use?

In general, large crochet hooks are used with thicker yarns. Smaller crochet hooks are used with thinner yarns.

There are a few ways that you can know what size hook you need for your project.

Yarn Label

The yarn label will give you a lot of information about the yarn’s fiber content and what size tools to use. 

Somewhere on the back of the label, you’ll see a series of squares. Look for the square with the drawing of a crochet hook inside.

The numbers next to the crochet hook give your the recommended size hook for that particular yarn. The number above the hook is the metric size, and the number under the hook is the US letter and number.  

Pattern Instructions

If you are following a written pattern, the pattern designer will tell you what size hook to use.

Gauge Swatch

If you’re still unsure what size hook to use, make a gauge swatch and compare it to the pattern gauge information. If your gauge is too large, you can use a smaller hook. If your gauge is too small, you can use a larger hook.

a woman holding pink yarn and a pink crochet hook

How to Measure a Crochet Hook

The size of a crochet hook is determined by the diameter of the shaft. The size of the shaft determines the size of the yarn loops.

Most crochet hooks have the size marked on the hook, either on the thumb grip or down the side of the shaft. 

But what if you’ve found a vintage hook without sizing information, or the size label has worn off?

Not to worry, there are a few ways you can measure a crochet hook to find its size. 

Hook Gauge Tool

The first way to measure a crochet hook is with a special tool called a hook gauge (sometimes called a needle gauge).

A hook gauge is a small plastic or metal card with a series of small holes, each labeled with its diameter measurement. Insert your hook into each of the holes to find the one that fits best. Then, read the size to know what size crochet hook you have.

Note: Due to inconsistency among crochet hook brands, I recommend double-checking your hook size using a measuring tool that includes both US and mm sizes.

Measuring Tape

If you don’t have a hook gauge tool, you can use a tape measure with millimeter markings. Lay the tape measure across the shaft of the hook to measure the diameter. This might not be the most accurate method of measuring a crochet hook, but it is a good place to start.

Make a Gauge Swatch 

A gauge swatch won’t tell you the size of your crochet hook per se, but it will tell you if it is the right size for your project. If you crochet a swatch in the same gauge as your pattern, you know you’re using the correct hook. On the other hand, if your tension is off, you’ll know if you have to go up or down a hook size.

a variety of pink an purple crochet hooks in front of pink yarn

Types of Crochet Hooks

There are many types of crochet hooks on the market. The kind of crochet hook you use depends on the project and your personal preference. Here are a few common styles:

Aluminum: Aluminum crochet hooks are inexpensive and widely available. They are quite popular, especially among beginners. They are available in a variety of sizes and colors. 

I often recommend aluminum hooks since the yarn glides smoothly over the smooth surface.

Plastic and resin: Plastic hooks are so fun and colorful! They are often used for larger sizes since the material is so lightweight.  

Bamboo and wood: Wooden crochet hooks are a pleasure to hold in your hand. They aren’t as slick as aluminum hooks, so they may work better for some types of yarn. Wood hooks are not available in the smallest sizes. 

Ergonomic: These crochet hooks have larger soft handles designed to reduce strain in your hands. They can be made from wood or plastic.

Tunisian: Tunisian crochet hooks are longer than a standard crochet hook and may have hooks on both ends. They are used for a particular type of crochet, called Tunisian crochet.

The Knook: This is a specialty crochet hook with a hole through one end. With the Knook tool, you can create stitches that look like knitting.

Steel: These are the smallest crochet hooks that are used for thread crocheting.

Popular Crochet Hook Brands

If you are shopping for some new crochet hooks, let me recommend some of my favorites.

Regular Crochet Hooks: These are my favorite crochet hooks, and the ones that I recommend to beginners. They have soft, comfortable hands and

Steel Crochet Hooks: I like this set of Amour Steel Crochet Hooks from Clover. They have comfortable soft rubber hands that reduce hand stress and fatigue.

Ergonomic Wood Hooks: These crochet hooks from Furls are some of the most beautiful tools around. They are handmade with a lightweight polished handle that’s comfortable to hold.

Explore More Crochet Ideas

If you love to crochet, you may be interested in these related posts.

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pin image for crochet hook size chart with us and metric conversions
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