Crochet Hook Size Chart: Which Hook for 2 Ply, 3 Ply, 4 Ply and 8 Ply Wool

Buying wool and a crochet hook together? The hook size should match the yarn. If the hook is too small, the fabric becomes stiff and hard to work. If it is too big, the stitches look loose and holey. This simple guide shows which crochet hook to buy for each ply of wool, so you can shop for both at the same time.

Crochet hook size chart by ply

These are general guides. Brands differ, so the hook size printed on the yarn label always comes first.

How to read the yarn label

Most yarn labels show a small hook symbol with a number next to it, for example “3.5 mm” or “3.5 to 4 mm”. That is the hook size the maker recommends. Some labels only show a knitting needle size. In that case, a crochet hook of the same size or about half a millimetre bigger is a good starting point.

When to go up or down a size

• Go smaller if your stitches look loose, for tight items like amigurumi toys, or when you want a firmer fabric for bags and shoes.
• Go bigger if your work feels stiff, if you crochet tightly, or for soft, drapey items like shawls and baby blankets.
• Everyone’s tension is a little different, so make a small test square first and see how it looks and feels.

Which hook is best for baby clothes?

Most baby dresses and cardigans are made with 3 ply or 4 ply yarn, so a 2.5 mm, 3 mm and 3.5 mm hook will cover most projects. For warmer hoodies and jackets in 8 ply (DK), add a 4 mm hook. If you are a beginner, buying a small set from 2 mm to 6 mm is the easiest way to be ready for any yarn.

Choosing the hook material

• Aluminium: smooth, affordable and long-lasting. A good everyday choice.
• Steel: used for very small sizes and fine lace thread.
• Bamboo or wood: warm and light, with a little grip, which helps with slippery yarns.
• Ergonomic handle: a soft, thick grip that is kinder to your hands during long projects.

Read more in our guide to every type of crochet hook.

Shopping checklist

• Check the ply and the hook size on the yarn label.
• Buy the recommended hook, plus one size up or down if you can.
• Buy enough balls from the same batch (dye lot) so the colour matches.

Want to understand ply in more detail? Read our yarn ply guide and our best yarn for baby clothes guide.

Prefer a ready-made piece?

If you would rather skip the hooks and yarn, every Mazagia piece is handmade to order. Message us on WhatsApp for a custom crochet dress, cardigan or set.

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