Confused about yarn weights?

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If you are like me, you probably enjoy reading knitting books and magazines from all over the world. And that's where it can get really confusing. Have you ever despaired over trying to work out which kind of yarn you should use for a pattern you like, or which needle size is required?

The thickness of a yarn is referred to as "yarn weight".

Unfortunately, each yarn weight has different names in different countries, making it difficult to keep track of them all. 

For example, yarns requiring 4mm needles are usually referred to as "8ply" in Australia, "DK" or "double knit" in the UK and "light" or sometimes "light worsted" in the US, whereas in continental Europe, you would most likely refer to the needle size and the tension when describing the yarn (4mm, 22sts per 10cm). 

And as if that was not complicated enough, there are also different names for needle sizes, depending on which version you use. For example, 4mm needles are the same as American size 6 needles and UK/Imperial size 8 needles.

And then you have yarns that may have the weight of an 8ply or a 12ply but that are actually single ply or lopi-style yarns. 

Get it wrong, and your project will not be the size you thought it would be! 

At I Wool Knit we support the efforts of the Craft Yarn Council which has developed standards and guidelines for crochet and knitting in consultation with international manufacturers and trade associations. You can find a summary of the official standards at

Unfortunately, the Craft Yarn Council does not give any indication of "ply" - which is what many of our Australian knitters like to use as a reference. 

For yarns where the yarn manufacturer does not specify "ply", we use the classification at Ravelry as a guide.

As a general guide, we always recommend that you check the recommended tension and the needle size, as we find this to be a better guide than "ply", especially when it comes to yarns made from fibres other than wool. 

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