Understanding Crochet Hook Sizes & Conversion Chart (2024)

FAQs

How do you explain crochet hook sizes? ›

Hook sizes are generally given in mm (eg. 4mm) which refers to the thickness of the hook. The higher the number, the thicker the crochet hook, so a 10mm hook is thicker than a 7mm hook.

A crochet hook conversion chart is a valuable tool that can be used to determine the correct hook size for a specific yarn weight. It can also be used to help convert stitches from one size to another. As a result, it is an essential tool for every crocheter.

As a general rule you can say that, the bigger your crochet hook, the more yarn you grab. The thinner you choose your crochet hook, the smaller the gaps between your stitches turn out. Also the stitches will be leaning much tighter against each other compared to using a bigger hook.

A crochet hook conversion chart, as shown below, can help explain the differences between systems. In general, the USA uses letters, which go up as the hook gets bigger (so a C hook is bigger than a B, for example). Japan uses ascending numbers, with a 2 hook being very small and a 10 being very large.

Determining fishing hook sizes is a bit of a formula, with the measurement based on the distance between the shank and shaft of the hook and the length of the shaft. The bigger the number (#), the smaller the size until #1. At that point, the sizing system changes, increasing from 1/0 to 2/0 and so on.

Crochet hook sizes for beginners

You don't need to have all the different sizes in your hook stash to start crocheting. You'll probably find you use 3mm and 4mm hooks most often, so start off with these.

Using a smaller crochet hook can result in a tighter gauge, which makes the finished item denser and less airy than if it were done using a larger hook. A denser fabric is often preferred, especially for projects like amigurumi, where a tight structure helps maintain the shape and form of the stuffed toy.

Go down a hook size for a tighter fit. Adjust length by the amount of rounds you do. If you need a longer sweater, simply add rounds/rows of the garment until you get the length you need. You can also work less rounds/rows if you need a shorter garment.

Eyeball Your Yarn

An old eyeball trick I was taught was to lay the yarn side by side to a few crochet hooks. The hook should be a little thicker than the yarn, but not by much. They should almost be the same thickness. This is one way to eyeball your yarn and guess which hook best matches the yarn.

If you use too small of a crochet hook, your crochet fabric will be stiff with no drape in the fabric—think more like stiff, felted fabric. If you use too large of a crochet hook, the resulting crochet fabric will be loose with very little stitch definition and large holes in the fabric.

What is the most popular crochet hook size? ›

Just from general experience crocheting, designing and following other designer's patterns, it appears that the most used crochet hook size ranges from 4mm (G-6) to 5.5mm (I-9).

Benefits of a Larger Crochet Hook

Faster progress: Bigger hooks can help you complete projects more quickly since they create larger stitches. Looser stitches: Larger hooks produce looser stitches, which can be suitable for certain projects like blankets and scarves that require a more relaxed drape.

Each yarn will have a recommended crochet hook size to be used with it, depending on the yarn weight. The thicker the yarn, the larger the hook size you will need to use with it. For example most DK yarns recommend a 4mm hook, whereas chunky yarns use a 6-7mm hook.

A size 7 crochet hook is a 4.50mm crochet hook and is right between a G and a H hook, if you're using the US terminology. We tend to not use this size often in the United States, but we really should as there is quite a gap between a 4.00 mm G hook and a 5.00 mm H hook!

Understanding Crochet Hook Sizes

The larger the hook, the thicker the hook will be - sounds about right! In the USA, we organize crochet hooks by letters, with the further down the alphabet you go, the thicker your crochet hook will become. So a B hook will be smaller than an E hook.

For example, the crochet hook size that is most commonly used for worsted weight yarn is an 'H', which is sometimes called a 'size 8'. From an international point of view, this number is incredibly confusing! Most countries identify crochet hooks by their size in millimeters (mm).

Just from general experience crocheting, designing and following other designer's patterns, it appears that the most used crochet hook size ranges from 4mm (G-6) to 5.5mm (I-9).