Yarn weights are a way of classifying yarns based on their strand size and/or how they work up on the recommended needle size.  When we talk about the weights of yarn, it refers to the thickness of the strand, not the weight of the ball.  Most yarns will fit into one category (with exceptions), but there is still some variation within the weights that can complicate things a little.

Use our guide to take a look at most of the weights you will come across when you craft with yarn; the difference between them; and examples of the things you could use it for.  Please note that the terms we use in this guide are part of the UK system for weight classification – other systems are used in other parts of the world.

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Ply

It can be confusing because the word ply is often used to describe two different things when discussing craft yarn.  The  ply of a yarn can refer to both the structure of a yarn (i.e. the number of threads that make up the strand) and the weight of the finished yarn. For example, a Chunky yarn may be made up of two plied strands but would not be 2 ply weight, and you’ll find many yarns that are single-ply but are definitely not 1 ply in weight!

Different plys of yarn

2 ply, 3 ply, 4 ply, 6 ply, and 8 ply in our guide refer to the weight of the yarn, not the actual ply of the strand.

Thread

The Thread yarn weight listed on our website is for all the crochet threads that we stock.  Crochet thread has a weight system of its own, where each thread is listed by a number from 3 to 100, with the strand getting smaller as the number gets bigger.  Crochet thread is typically thinner than craft yarn, and the thickest crochet thread (size 3) is approximately equal to a fingering or 4 ply weight yarn.

Lace Weight

Lace weight yarns have extremely light and thin strands that are used for decorative pieces and delicate accessories, often shawls.  They are either knitted on very thin needles, or larger needles to create a draping, cobweb effect.

1 Ply

Whilst the number of threads used doesn’t always give an indication of the weight of the yarn, 1 Ply yarn is exactly as it sounds!  Made from a single, very thin strand, 1 ply yarn is much like Lace weight in that it is used to make very lightweight pieces, but the fibres used are spun only once and the strand is not made from multiple twisted threads.  This provides a very fine and very smooth texture that is perfect for intricate work.

2 Ply

Only slightly thicker than 1 ply yarn, 2 ply yarn is often used for baby projects or intricate crochet projects, and for this reason you’ll quite often find that these yarns are either cotton or an acrylic/acrylic mix. The slimmer strand makes it easier to craft smaller items, like amigurumi projects, or very light blankets and shawls.

3 Ply

3 ply is another weight that is often used for baby yarn, as well as for some sock yarn. 3 ply yarns are ideal for complex and detailed colourwork, such as traditional Fair Isle patterns. Many garments and blankets for premature babies use 3 ply as it is thick enough to make warm blankets and garments, but thin enough to make light items that are perfect for delicate skin.

4 Ply

There are many projects which are perfect for 4 ply but, most commonly, this weight is used for socks. Many baby yarns are also 4 ply, as well as plenty of yarn for knitted jumpers but, because it will take longer to create in this weight, for the more patient crafter! Although the pieces knitted from this ply yarn will be light and thin, they will not be as lacy as a lower ply.

6 Ply and 8 Ply

6 and 8 ply yarns are not frequently used yarn weights in the UK. They are a little lighter than a DK and are most usually used for sock making.

Sport/Baby weight

Sport and Baby weight yarns can be confusing as weight classifications, as Baby weight is sometimes categorised with 4 ply, whilst Sport weight is sometimes categorised with DK. Most often, though, they will be together in a weight class of their own, positioned between 4 ply and DK. Checking the tension on the ball band will help to clarify the weight. These yarns are perfect for lighter weight garments.

DK (Double Knitting)

One of the most popular weights in the UK, DK weight yarns are suitable for all kinds of garments, accessories, toys and home furnishings. There are an enormous range of different types of patterns for DK yarns, as well as a huge range of colourways. DK is a great choice for a mid-weight, versatile yarn.

Worsted

Heavier than a DK but a little lighter than an Aran, Worsted appears less often in UK classifications, but you can find this classification on yarn produced internationally. You may find that Worsted and Aran are used interchangeably, but be sure to carefully check the tension on the ball band if you are intending to substitute one for the other.

Aran

The ultimate jumper weight yarn! Aran weight yarn has all the versatility of a DK with all the fast-crafting thickness of a Chunky weight. Traditional-style yarns are very often made in an Aran weight, such as yarn for fisherman’s jumpers, as this is the perfect weight for heavier autumn/winter accessories and cosy garments that will keep out the cold.

Chunky

A great weight for beginners, Chunky yarns make it much easier to see what you’re doing, and also works up satifyingly quickly! Whilst not so good for small, more delicate items, or for colourwork, Chunky yarns are available in amazing colour mixes, as there is much more surface area on each strand to show the colour changes.

Super Chunky

Super Chunky is the weight classification for everything over a Chunky weight. As you can imagine, this covers a lot of different strand thicknesses! When considering Super Chunky weight yarns, it is more important than ever to look at the tension, as this is the only way to ensure you are going to get the size of yarn you need. Super Chunky yarns are great for finger and arm knitting and are often used for blankets and similar home accessories.

Roving

Roving is the weight group for unspun fibres that are usually used for spinning and felting. Whilst some of the larger balls of Roving are used for arm knitting and the creation of giant home decorative pieces, most of the smaller packs cannot be knitted as they are and need to be spun beforehand. You will also find Roving available in smaller packs and large selections on colours, perfect for wet and dry felting.

Fashion and Scarf

Fashion and Scarf yarns tend to be in a category on their own as their unique construction can make them hard to classify. They include ribbon yarns, pom pom yarns, sequined yarns, and also accent threads for use alongside a thicker strand of yarn. Whilst you can find tension information on some fashion yarns, some will be harder to match to a specific pattern, requiring a little more ingenuity from the crafter!

Yarn weight is a pretty important thing to understand when you’re learning to craft, but it’s also important to know that all yarns are unique and, whilst most will fit neatly into one of these categories, it’s not always possible to be exact. Some yarns will be thinner than others, despite being in the same weight category, and you’ll find some spread out into the categories either side, creating crossover and adding to the confusion! It’s sometimes really useful to take a look at what other people have made with different yarn weights, to give you a better idea of the differences. If it all seems confusing at first, it will all become clearer as you begin your crafting journey.

if you find any of these instructions unclear, or just need a little extra help, don’t hesitate to email us at sales@woolwarehouse.co.uk or give us a call on 01926 88 28 18.