Yarn Weights Explained: A Beginner’s Guide

Why are some yarns so thin?

And why are some yarns so thick?

If you’ve ever wondered what the thickness and thinness of yarn is all about, this guide is for you!

This post will go over each yarn weight, their nicknames, what they are and what they’re good for. Watch my video to get an overview of all the seven weights:

Some yarns are thick and sumptuous while others are skinny like a spiderweb. Others are in-between and some defy category (fun fur, anyone?).

Like people, yarns come in many shapes and sizes. So, in order to talk about the bigness or smallness of yarns, the Craft Yarn Council designed the Standard Yarn Weight System to categorise all the weights.

I call it the yarn weight family because a family feels cosier than a “system.” But the idea is still the same. So without further ado, let’s meet the yarns, from the thinnest to the thickest.

Download a free PDF of the yarn weight family by clicking the button above.

Size 0 – Lace

Lace weight is the thinnest and lightest type of yarn. It’s commonly used to knit open lace projects like shawls, scarves and doilies.

The result is a delicate ethereal fabric that’s incredibly lightweight.

It’s rare to knit a dense compact fabric with lace weight yarn using tiny needles. It’s more common to use larger needles to create an open lacy fabric.

This lace weight yarn is a mix of mohair and silk. It’s Valley Yarns Southampton in color Tang.

These days it’s trendy to knit with a strand of lace weight yarn held together with a thicker yarn to create a dense and fuzzy fabric.

Lace Weight Gauge:

Knitting and crochet gauge is 8-10 sts per inch.

Needle sizes can be as tiny as 1.5-2.25mm but lace yarn is normally knit with larger needles, up to 5mm, to create an open lacy fabric.

Size 1 – Super Fine Weight Yarn

Super fine yarn is also called sock, fingering and 4-ply yarn. It’s often used to knit socks, shawls, mittens and other small accessories.

Sock knitting is still popular among knitters, who favour this weight for its fine gauge and texture.

 

A note about the term 4-ply

The term “4-ply” is most commonly used in the UK and Europe.

However, to make things more complicated: a 4-ply weight yarn doesn’t necessarily have 4 plies of yarn.

A ply is a smaller strand of fibre that’s spun together to create a single strand of yarn.

The yarn on the left has 4 plies of yarn twisted together to create one strand of yarn.

So, while a yarn can be 4-ply weight, it may only have two plies of yarn, like the yarn above on the right.

Super fine yarn is slightly thicker than lace weight and uses the tiniest needles.

The yarn used here is Paintbox Yarns Cotton 4 Ply in the colour Flamingo

Super Fine Gauge

Knitting gauge is 6-8 sts per inch with a 2.25-3.25mm needle
Crochet gauge is 5-8 sts per inch with a 2.25-3.5mm hook

Size 2 – Fine Weight Yarn

Fine yarn is also called sport and baby weight yarn.
This is a versatile yarn that’s commonly used for baby and children’s clothes and accessories.

It’s also used for athletic wear (hence the name “sport” weight) because it knits into a lightweight fabric with a delicate drape and great stitch definition.

This is a great yarn weight for spring and summer garments because of its light weight.

I chose sport weight yarn to design my Fingerless Mittens because of its fine gauge.

For small accessories like mittens I like sport weight because the gauge seems to match the smallness of the accessory.

The yarn I’m using is Debbie Bliss Baby Cashmerino in color Royal

Fine Weight Gauge:

Knitting gauge is 5-6.5 sts per inch with a 3.25-3.75mm needle
Crochet gauge is 4-5 sts per inch with a 3.5-4.5mm hook

Size 3 – Light Weight Yarn

Light yarn is also called DK weight, light worsted yarn or 8-ply yarn.
“DK” is short for “double knit”.

This refers to the fact that it is double the weight of super fine yarn (also known as 4-ply yarn). With this in mind, you’ll also understand why this weight is called 8-ply yarn (it’s double the weight of 4-ply yarn).

DK weight is a bit of an in-between yarn: not thin but not exactly thick.

It can be used to knit all the same things as fine and worsted yarn, which makes it very versatile.

Sweaters and cardigans for adults and children knit up quickly in this yarn weight. It’s also great for baby blankets.

The resulting fabric is light, which makes it great for spring and fall garments, but not quite thick enough for winter garments.

I love knitting tank tops and other summer garments in this yarn weight. It’s thick enough that the knitting goes quickly, but thin enough that the fabric is still light and breathable.

The DK yarn used is Valley Yarns Superwash DK in the color Misty Lilac. It’s super soft and has incredible bounce. Because it’s a superwash yarn, it’s perfect for baby and children’s clothes and accessories.

Light Gauge:

Knitting gauge is 5-6 sts per inch with a 3.75-4.5mm needle
Crochet gauge is 3-4.5 sts per inch with a 4.5-5.5mm hook

Size 4 – Medium Weight Yarn

Medium yarn is also called worsted or aran weight yarn.

I find the term “aran” used more in the UK and Europe whereas “worsted” is more commonly used in North America.

Worsted weight yarn is the most popular yarn weight. It’s not too big and not too small: it’s just right for most projects.

I think of worsted yarn as the all-purpose yarn. You can knit just about anything with it: sweaters, cardigans, blankets, accessories, house socks, slippers and more!

I’ve designed a handful of patterns in worsted weight yarn, including the Baby Bobble Blanket, Simple Shortie Socks and Slouchy Hat.

The worsted yarn used is Paintbox Yarns 100% Wool Worsted Superwash in the colour Pillar Red. It’s a good workhorse yarn with generous yardage and a wide range of colours.

Medium Weight Gauge:

Knitting gauge is 4-5 sts per inch with a 4.5-5.5mm needle
Crochet gauge is 2-3 sts per inch with a 6.5-9mm hook

Size 5: Bulky Weight

This weight is also called chunky and craft weight yarn.

Bulky yarn is cozy and thick. It knits up really quickly, making it a great instant gratification knit.

Because the yarn is thick, it’s usually used for cold weather projects like blankets, jackets, leg warmers, mufflers, scarves, cowls, and hats.

You wouldn’t knit light summer garments in bulky weight yarn because the weight of the yarn produces a dense heavy fabric that’s meant to keep you warm.

The bulky yarn used is Paintbox Yarns 100% Wool Chunky Superwash in colour Slate Green.

Bulky Weight Gauge:

Knitting gauge is 3-4 sts per inch with a 5.5-8mm needle
Crochet gauge is 2-3 sts per inch with a 6.5-9mm hook

Size 6 – Super Bulky

This is a winter yarn that’s really thick and warm. It’s usually made of wool, alpaca, acrylic or a blend of these fibres.

Because it’s so thick, it knits up really quickly, making it perfect for last-minute projects.

You’re unlikely to find a super bulky yarn in plant fibres like cotton, bamboo or linen. This is very much a cold weather yarn that’s meant to keep you warm.

Super bulky yarn is ideal for blankets, warm winter garments like jackets and sweaters, and accessories like scarves, cowls and hats.

This super bulky yarn used is called Chester by Valley Yarns in color Olive. It knits up into a boucle texture, which is so satisfying to touch. I can imagine knitting the cosiest cushions with this yarn!

Super bulky yarn is my favourite yarn weight. I’ve designed so many patterns around it because I love its cozy texture and how quickly it knits up!

Super Bulky Gauge:

Knitting gauge is 1.75-2.75 sts per inch with a 8-12.75mm needle
Crochet gauge is 1.75-2.25 sts per inch with a 9-15mm hook

Size 7 – Jumbo

This yarn, as the name implies, is really super big!

While arm knitting is common for this yarn, using really large needles or hooks is also possible but not that comfortable.

Because this yarn is heavy, it can cause strain on your arms and shoulders as you’re working it. Thankfully, projects come together really quickly because this yarn is enormous.

Jumbo yarn is rarely used for garments because it’s just too heavy and cumbersome to move around in. It’s often used for home accessories like baskets, blankets, rugs, and floor poufs.

A similar jumbo yarn used in this post is available on Amazon.

Jumbo Weight Gauge:

Knitting and crochet gauge is 1.5 sts or less per inch with a 12.75mm needle or a 15mm hook. I’ve also seen broomsticks used as a knitting needle when working this yarn.

Wraps Per Inch (WPI) to Determine Yarn Weight

If you’ve got mystery yarn and you want to figure out its yarn weight, determine its wraps per inch (WPI)!

This is a nifty technique that requires a pencil and ruler.

Simply wrap the yarn around a pencil, allowing the strands to sit side-by-side.

Then count the wraps around the pencil that make up one inch. This is the wraps per inch!

My mystery yarn has 8 wraps per inch. According to the WPI chart here, my yarn is a bulky weight.

Mystery solved!

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