Crochet Hook Sizes Chart: mm, US Sizes and Which Hook for Your Yarn

Crochet hooks are sold by size, and the size changes how big your stitches are. A bigger hook makes bigger, looser stitches, and a smaller hook makes small, tight ones. This guide gives a chart of metric and US hook sizes, the hook that usually goes with each yarn weight, and the one rule that matters most for toys: use a smaller hook than the yarn label suggests.

Crochet hook sizes chart

Hooks are named by their width in millimeters (mm). In the US they also have a letter or number. The millimeter size is the reliable one, because letters and numbers vary between brands and countries. Old UK sizes use a different numbering, so always use the mm size to compare.

Very small hooks, such as 1.0 mm, 1.5 mm and 2.0 mm, are called steel hooks. They are used for thread, lace and tiny amigurumi, and they are usually listed by their mm size only.

Which hook for which yarn weight

The label on a ball of yarn gives a suggested hook size. These are the usual ranges for flat projects like blankets and scarves. Treat them as a starting point, and make a small swatch to check.

Hooks for amigurumi are smaller

For toys, use a hook one or two sizes smaller than the yarn label suggests. A tighter fabric stops the stuffing from showing through the stitches and gives the toy a firm shape. If you can see white filling through your crochet, your hook is too big or your tension is too loose. The pattern lists the hook it was written for. Use it, and swatch first if your yarn is different.

These are common starting ranges, not rules. Some patterns use a very small hook, such as 1 mm with fingering yarn, for tiny charms. The finished size changes with the yarn and hook, so the same pattern gives a bigger toy with thicker yarn and a bigger hook. Our guide to stuffing and assembling amigurumi explains how a tight fabric helps the finishing.

Choosing a hook that is comfortable

• Material: metal hooks let the yarn slide easily, wood and bamboo hooks grip it a little more, and plastic hooks are light. Try more than one kind to see which feels best.
• Handle: a thicker or softer handle is easier on the hand if you crochet for a long time.
• Head shape: some hooks have a pointed head and some a rounded one. A pointed head goes into tight stitches more easily, and a rounded one splits the yarn less.
• Start with one size for practice, such as 5 mm, before you buy a full set.

Why the same hook gives different results

Two people with the same hook and the same yarn can make fabric of different sizes, because everyone pulls the yarn with a different tension. This matters for clothes, where the size must be right. A gauge swatch shows how many stitches and rows you get in 10 cm (4 in). If you get too many stitches, use a bigger hook. If you get too few, use a smaller hook. For toys, an exact gauge matters less, but a tight, even fabric is still important.

How to read the hook size in a pattern

Patterns list the hook near the top, in the materials section, often with both mm and US sizes. If a pattern gives only a US letter and you work in metric, use the chart above. If it says "hook size to suit your yarn", check the yarn label, and then go down one size for toys. Our guide on how to read a crochet pattern explains the rest of the pattern information.

If you are starting out, read how to crochet for beginners, and then try one of our crochet patterns for beginners or a free crochet pattern. Each pattern lists its materials, including the hook size.