• Kelly

A Guide to Yarn - Everything you Need to Know

Yarn comes in many different forms, from cobweb to jumbo, solids to self patterning, smooth to slubby, there are so many things to know and learn about the stuff that it's no wonder we can spend hours in a yarn shop! So, when you have a new project to work on, how do you know which is the best yarn for you?

Let's start from the beginning; What is yarn?

Yarn is a long continuous length of interlocked fibres, commonly made from animal-based fibres, (wool, alpaca, angora, mohair, llama, cashmere, and silk), plant-based fibres (bamboo, linen, cotton, hemp, maize, nettle, and soy), or synthetic fibres (acrylic, polyester, nylon, and rayon). These interlocked fibres are spun together into thicker strands called plies. The plies (you may recognise it better as "ply") affect the drape, stitch definition, and general feel of the yarn.



WPI: 23-35 or more

(CAN INCLUDE 1, 2, & 3 PLY)

KNOWN AS: Lace, Thread, Cobweb, Light Fingering

USED FOR: Delicate shawls, doilies, and other lightweight items. Treat carefully to avoid breakage.


WPI: 19-22 (4 PLY)

KNOW AS: Sock, Fingering, 4ply, Baby

USED FOR: Socks, baby garments, hats, and other small projects.


WPI: 15-18 (5 PLY)

KNOWN AS: Sport, Baby

USED FOR: As above, sport weight yarn is used for smaller items like baby garments, hats, fingerless gloves etc


WPI: 12-14 (8 PLY)

KNOWN AS: DK, Light Worsted

USED FOR: A common, middle weight yarn, used for a number of items, including adult garments, hat,s gloves, scarves, etc


WPI: 9-11 (10 PLY)

KNOWN AS: Aran, Worsted, Afghan

USED FOR: As above, Aran weight is used for a number of items and provides great stitch definition with added warmth.


WPI: 7-8 (12 PLY)

KNOWN AS: Chunky, Bulky, Craft, Rug

USED FOR: Fast projects on large needles. Chunky scarves, throws, blankets. Great for beginners as the projects grow quickly.


WPI: 6 or less

(14 PLY) KNOWN AS: Super Chunky, Super Bulky, Roving

USED FOR: As above, fast projects on large needles. Super bulky works up even faster again.


USED FOR: Arm knitting projects, large blankets. Jumbo yarn must be treated after use to hold its integrity as it hasn't been spun. It is likely to pill (become bobbly) and felt in parts. It can become fuzzy and look old really quickly.

For a way to measure your WPI (wraps per inch), check out this blog post.

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Commonly Used Fibres


Wool yarn is great for winter and summer garments. It’s very warm for the cooler months, but it also has moisture-wicking capabilities which means it can keep you cool in the summer by pulling any moisture away from the skin. Wool also lasts a long time and can be easily cleaned by following the label directions.

However, it can be slightly itchy for people with allergies to some wool.

IDEAL FOR: Winter and Summer. It’s great for making scarves, sweaters, gloves, hats, socks, and other clothes.

RANDOM FACT: Wool has natural fire extinguishing properties, hence why it’s included in fire blankets. Other types of yarn don’t have this property.


Cashmere is one of the softest yarns around. From the fleece of a cashmere goat, this yarn is not as strong as sheep fibre and it can also be quite expensive. That's because cashmere goats shed their undercoat only once a year and, unlike sheep who are shorn, the goats' undercoat is combed and collected, which is very labor-intensive. The yield of fibre from one goat is about 4 ounces once it is processed. Which means it typically takes the fibres collected from four goats to make one jumper.

IDEAL FOR: It’s very soft and not itchy so it’s ideal for knitting clothing.

RANDOM FACT: 60% of the world’s cashmere is produced in China, Mongolia, and Tibet.


Alpaca is natural wool that comes from the South-American Alpaca. It's soft, fluffy and, almost silky, but it doesn’t hold its shape the same way sheep wool can. It’s usually a little more expensive and luxurious than regular sheep wool.

IDEAL FOR: A very warm fibre, perfect for knitting jumpers, hats, and cowls.

RANDOM FACT: Alpaca is water repellent and is also pretty anti-flammable.


Mohair is one of the warmest animal fibres despite being extremely light. It is very elastic and springs back to shape easily, so it resists wrinkling. Mohair is so fluffy that any stitch definition is lost but creates a beautiful halo of yarn around your project. It is often blended with silk or sheeps wool to add strength. However, it can irritate the skin causing itchiness despite having a low-allergenic risk.

IDEAL FOR: Cold weather clothes like jumpers, socks, hats, and scarves.

RANDOM FACT: Also known as The Diamond Fibre


A natural plant fibre, bamboo ages well and is sometimes considered to have natural antibacterial properties. It's very soft and has a wonderful silk like drape. It is also breathable and cooling on the skin.

IDEAL FOR: Garments and shawls which need good drape. Summer tops and jumpers.

RANDOM FACT: Bamboo can be softer than silk when spun into yarn.


Silk is hygroscopic, which means it absorbs moisture in the air, keeping you at a regulated temperature no matter the weather. It is super shiny, incredibly soft, and drapes like no other yarn. However, it is also an unforgiving fibre. The slightest shift in your tension will be noticed, so I would only recommend pure silk yarn to experienced knitters. A silk blend yarn is better suited to most knitters.

Silk is the most expensive and lustrous fibre on this list. Silkworms spin cocoons that silk producers eventually unravel and join to create the thread. The caterpillars are killed in the process, which makes silk a question of ethics for some people too.

IDEAL FOR: Luxury items like lace shawls and summer tops with beautiful stitch work.

RANDOM FACT: Silk is the strongest natural fibre known to humans.


Originating from the cotton plant, it's grown in warm climates like India, USA, and China.

Although it is light, breathable, and strong, it doesn’t hold its shape when blocking that well and your stitch definition may not be uniform. Unfortunately, cotton yarn production is quite harmful to the environment. The plants require significant pesticide, making up 16% of all insecticide and almost 7% of all herbicide use worldwide. However, it is biodegradable and you can purchase organic cotton so shop smart.

IDEAL FOR: Cotton is the perfect choice for summer knits, dishcloths, potholders, and face cloths.

RANDOM FACT: Cotton can absorb up to 27 times its own weight in water.


A man-made synthetic fibre that is usually much cheaper than most natural fibres. Acrylic washes easily, holds its colour well, and used to be the choice for beginner knitters. However, acrylic is extremely bad for the environment. It is plastic which means that it will take decades to completely break down and the production of acrylonitrile (the main compound used in acrylic yarns) uses a significant amount of fossil fuel, majorly contributing to climate change and global warming.

IDEAL FOR: Nothing. Not if we love our planet.

RANDOM FACT: Acrylonitrile is identified as being a potentially cancerous agent by absorption through the skin. My advice is to avoid acrylic yarn.

Understanding the Ball Band

With every ball, skein, hank, or cake of yarn, there is a label, also known as a ball band. Ball bands tell us everything we need to know, including yarn weight, suggested needle size, gauge to expect, fibre content, care instructions, and dye lot number. Let's work through each of these separately;

YARN WEIGHT: This is the yarn thickness. It may be stated in the name of the yarn, for example, "Rowan pure wool DK," or it could have a graphic of a ball of yarn with a number written in. The number corresponds to the categories I mentioned earlier.

When looking for the correct yarn weight for your pattern, try to get the same weight as the pattern states. If you buy chunky yarn for a DK pattern, you're going to end up with something much bigger than the item is intended.

ACTUAL WEIGHT: There is also the actual weight of the ball/skein you have. Most yarn comes in 50g or 100g but you can also buy 10g, 25g, and 500g.

LENGTH: Stated in meters and yards on most yarn bands, this is the length of yarn you are going to get inside the ball or skein. A pattern should state how much yarn you need to complete the project in either meters, yards, or both, and the ball bands help you to calculate how many balls/skeins you will need.

SUGGESTED NEEDLE SIZE: This is the needle that will work best with the yarn.

GAUGE: This is the gauge you can expect an average knitter to achieve using this yarn with the suggested needle size. That's not to say you will definitely get that gauge as you may knit tighter or looser than the average knitter..

FIBRE CONTENT: Speaking for itself, this tells you the fibre content of your yarn in percentages. It may be 100% merino, it may be 75% merino, 20% cashmere, and 5% silk.

CARE INSTRUCTIONS: The necessary instructions to care for your garment or accessory once it's knitted. This is most likely in symbols so you will need to know what each one means. Some instructions are different depending on where the yarn originates. For example; The symbol for Do Not Bleach is a clear triangle with a cross through in the EU but it is a black triangle with a cross through for the USA

DYE-LOT NUMBER: This number refers to the dye batch which was used when dyeing that particular ball/skein of yarn. When buying multiple balls/skeins, make sure to check this number and get the numbers that match. Even if the colour looks the same while holding them together, the subtle difference can really show when knitting.

Choosing Your Yarn

Whenever you start a new pattern, a section will tell you which type of yarn to use. Some patterns will give you enough detail about the weight (4ply, DK, Aran etc), others will just state the yarn that was used to create the sample. Either way, with a bit of research, you can discover which yarn weight is best for the pattern, plus the needle size and gauge required. This is always the best starting point when purchasing yarn for a new project. You never have to use the yarn stated exactly by the designer, you can always choose something that suits you best. Sticking to yarn weight, and in particular, gauge, is a huge must to get the outcome you require.

When you're designing your own pattern consider what the design needs. A baby item may need to be machine washable and probably not knitted in silk. A floating shawl would need to be lightweight and not made from heavy cotton. Consider if winter gloves should be made in a cobweb lace or a sturdy Aran. Ultimately, the decision is yours and the yarn world is very much your oyster.

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