Yarn is the most important component of knitting. The qualities of the yarn affect the final product, no matter how experienced of a knitter you are. Of these qualities, yarn weight has the biggest impact, making it vital that knitters understand it when selecting the right yarn for a project.
We go into the details below, but we also put this info into an awesome infographic!
Table of Contents
- What Does Yarn Weight Mean?
- Understanding Yarns
- Yarn Structure
- What’s a Ply?
- Why Yarn Weight Standards Matter
- How to Determine Yarn Weight
- The Wrap Method
- Yarn Weight and Knitting Needle Size Chart
- A Detailed Breakdown for US, UK, Australia and New Zealand
- Super Fine
- Super Bulky
What Does Yarn Weight Mean?
Yarn weight can be pretty confusing, especially if you’re just starting out on your knitting journey. At first glance, you might think that yarn weight is about how much a ball or skein weighs in ounces or grams on a scale. Nope!
Yarn weight refers to the thickness of the yarn. It ranges from yarn as thin as sewing thread to yarn thicker than your arm. Some yarn weights are best suited for lace knitting, while others are used for sweaters or rugs. The success of your knitting project depends on selecting the right yarn weight.
Yarns are made from fibers – plant, animal, mineral, cellulose, and plastic. The fiber composition affects how the yarn knits (such as elasticity and slipperiness) and how your final project appears.
Fibers can be combined to create yarn, such as 50% silk and 50% linen, allowing the yarn to inherit qualities from each type of fiber used.
How the fibers are processed and spun impacts the final yarn weight.
When fiber strands are twisted together, yarn is created. This process of twisting fibers is known as spinning. This helps give yarn its structure.
When yarn is twisted, a spiral is formed. The spiral can run upwards to the left (called an S twist) or upwards to the right (called a Z twist). The Z twist is the standard.
Note: Not all yarn is spun. Examples include chenille, paper, ribbon and roving. Roving is a continuous strand of fiber that has been left unspun. Most types of roving need to be spun in order to produce a fiber that is strong enough for knitting. Roving from Icelandic wool is one exception, naturally strong enough to be knit while unspun.
What’s a Ply?
Yarns are plied (twisted) together to increase their strength and uniformity. To ply yarn, individual strands of spun yarn are spun together with the twist worked in the opposite direction of how the single strands were spun. For example, if the single strands had an S twist, the plied strands would be made with a Z twist.
A single strand of spun yarn is called a single, not a single ply or 1 ply. Yarn only has a ply after singles are twisted (plied) together. A two-ply yarn is created from twisting together two singles, a three-ply yarn is made from three singles, and so on.
Plying strands of yarn together is important because singles can bias (lean) when knit. When two singles are plied together, the twisting of the yarns in the opposition direction of the original spinning removes the skewing.
If you look at sweaters you have bought at a store, you should notice that they are made with single strands of yarn, not plied yarn. This is one reason hand-knit sweaters are considered superior and longer-lasting than industrial machine knitted sweaters. It might be easier and faster to buy a store-made sweater, but is it worth it?
I’m inclined to say no. It’s why I’ve made all of my sweaters for years. No industrial machine knitted sweaters in my closet! And it gives me another reason to grow my yarn stash! Win win!
While some countries, such as Australia and New Zealand, use ply to designate yarn weight, the number of plies in a yarn doesn’t necessarily indicate how thick the yarn is. Instead, how tightly or loosely the plies are spun together determines the thickness. Thus, a tightly spun four-ply yarn can be thinner (and a smaller yarn weight) than a loosely spun two-ply yarn.
Why Yarn Weight Standards Matter?
Because the term ply makes it confusing to know exactly how thick or thin a yarn is, a system of standards was created by the Craft Yarn Council of America. This system makes it possible to substitute yarn, no matter where you are in the world.
The system uses a scale from 0 to 7, with 0 being the finest yarn (known as lace) and 7 (known as jumbo) being the biggest.
How to Determine Yarn Weight
Most yarn manufacturers use the yarn standards ranking system created by the Craft Yarn Council. You can find the yarn weight printed on the label.
But what if your yarn has lost its label or no weight is printed on it? You can calculate it easily using the wrap method.
The Wrap Method
The wrap method is a simple method you can do at home to determine the weight of a mystery yarn.
You will need:
- Your mystery yarn
- A ruler
- A uniformly sized cylinder, such as a pencil, screwdriver or empty cardboard paper towel tube
- A pen or pencil that can be used to mark your cylinder
- Use a ruler to measure 1 inch (2.5 cm) on your cylinder and mark the measurement with your pen or pencil.
- Starting at the beginning of the 1 inch (2.5 cm) mark, wrap your yarn around your cylinder, wrapping the yarn as close as possible without overlapping or leaving holes. You don’t want to wrap the yarn too tightly or it’ll stretch thinner than it actually is, but you also don’t want it so loose it’s hanging off the cylinder. Wrap until you reach 1 inch (2.5 cm).
- Count the number of times you wrapped the yarn in the 1 inch (2.5 cm) space. The number of wraps will tell you the yarn weight (see Standards for Yarn Weights Chart below).
Yarn Weight and Knitting Needle Size Chart
Our yarn weight comparison chart makes it easy to know your yarn’s weight and what knitting needle size to use. It’s based on the Craft Yarn Council’s Standard System.
|Wraps Per Inch (WPI)||Gauge per 4 in / 10 cm||Needle Size||US||UK||Australia/New Zealand|
|O Lace||at least 16||33-40 stitches||1.5-2.25 mm;
|1 Super Fine||15||27-32 stitches||2.25-3.25 mm;
|Fingering, Sock||4 Ply||4 Ply|
|2 Fine||12||23-26 stitches||3.25-3.75 mm;
|Sport||No equivalent||5 Ply|
|3 Light||11||21-24 stitches||3.75-4.5 mm;
|4 Medium||8-9||16-20 stitches||4.5-5.5 mm;
|5 Bulky||7||12-15 stitches||5.5-8 mm;
|6 Super Bulky||5-6||10-11 stitches||8-12.75 mm;
|Super Bulky, Roving||Super Chunky, Roving||No equivalent for spun yarn, Roving|
|7 Jumbo||0-4||6 stitches or less||12.75 mm and larger;
US size 17 and larger
Standards for Yarn Weights – A Detailed Breakdown for US, UK, Australia and New Zealand
The US, UK, Australia and New Zealand often use different terms for the same yarn weight. When you know the terms used, it’s easy to substitute yarn – no matter where you live!
Lace weight yarn has at least 16 wraps per inch (wpi).
Its knit gauge is 33-40 stitches per 4 in / 10 cm on 1.5-2.25 mm needles (US size 000-1 needles). However, lace yarn is usually knit on larger needles to create a more airy, lace-like effect.
This standard of yarn weight is the broadest as it refers to a wide range of yarn thicknesses, with their common element being their use in lace knitting. There are 4 types of lace weight yarn:
- Thread – This yarn is also called gossamer or feather-weight. It has the same thickness as sewing thread or 10 count crochet cotton. It is so thin that even experienced knitters can find it challenging to knit.
- Cobweb; also known as 1 ply in the UK, Australia and New Zealand.
- Lace-weight – Lace-weight (note the hyphen in the name) is the most common term used for all lace weight yarn in the US, but it is known as 2 ply in the UK, Australia and New Zealand.
- Light fingering in the US; known as 3 ply in the UK, Australia and New Zealand
Lace yarn is commonly used for lace knitting and knitted lace.
1 Super Fine
Super fine weight yarn has 14 wpi.
It’s normally knit at a gauge of 27-32 stitches per 4 in / 10 cm on 2.25-3.25 mm needles (US size 1-3 needles).
In the US, it is commonly known as fingering weight or sock weight. Sock weight is a term often used for this yarn weight because it is frequently used to make socks. However, sock weight is a term, not a standard yarn weight.
In the UK, Australia, and New Zealand, super fine yarn is known as 4 ply.
Super fine weight yarn is commonly used for lightweight accessories (such as shawls and scarves) and socks.
Fine weight yarn is 12 wpi.
Its knit gauge is 23-26 stitches per 4 in / 10 cm on 3.25-3.75 mm needles (US size 3-6 needles).
In the US, fine weight yarn is referred to as sport, while in Australia and New Zealand, it is called 5 ply. No equivalent exists in the UK.
Fine yarn is commonly used to make light sweaters, baby garments, and accessories.
Light weight yarn has 11 wpi.
It’s knit at a gauge of 21-24 stitches per 4 in / 10 cm on 3.75-4.5 mm needles (US size 5-7 needles).
In the US and UK, light yarn is commonly called DK, while it is known as 8 ply in Australia and New Zealand.
This yarn is normally used to make sweaters and lightweight scarves.
Medium weight yarn has 9 wpi if it is worsted and 8 wpi if it is aran.
It has a knitting gauge of 16-20 stitches per 4 in / 10 cm on 4.5-5.5 mm needles (US size 7-9 needles).
In the US, medium weight yarn is called worsted yarn and is slightly thicker than its equivalent in the UK – aran yarn. Both US worsted and UK aran yarns are equal to 10 ply Australian and New Zealand yarns.
While the term “worsted” refers to a spinning method, in the US, the term worsted yarn also refers to medium-weight yarn. This can be confusing, particularly when dealing with hand spun yarn, as you can find worsted DK hand spun yarn. Be certain to double-check what worsted refers to when knitting with hand spun worsted yarn from the US – the spinning method or the yarn weight.
Medium weight yarn is commonly used for sweaters, blankets, hats and mittens.
Bulky weight yarn has 7 wpi.
Its knitting gauge is 12-15 stitches per 4 in / 10 cm on 5.5-8 mm needles (US size 9-11 needles).
It is commonly called bulky in the US, chunky in the UK, and 12 ply in Australia and New Zealand.
This yarn can be hard to successfully substitute because it can vary a lot in thickness.
It is normally used to make rugs, jackets and blankets.
6 Super Bulky
Super bulky weight yarn has 5-6 wpi.
Its knitting gauge is 7-11 stitches per 4 in / 10 cm on 8-12.75 mm needles (US size 11-17 needles).
It is known as super bulky in the US and super chunky in the UK. It doesn’t have an exact equivalent in Australia and New Zealand, but if you can find anything thicker than a 12 ply, you might find success.
Roving is a super bulky weight yarn.
Super bulky yarn is commonly used to make sweaters, rugs and heavy blankets.
Jumbo weight yarn is a relatively new addition to the system of yarn weight standards.
It has 0-4 wpi. Its knitting gauge is 6 stitches or less per 4 in / 10 cm on 12.75 mm and larger needles (US size 17 and larger needles).
This yarn is roving. It is used for arm knitting, knitting with PVC pipe, and knitting with broomstick sized handles.
Jumbo yarn is typically used to make heavy blankets and rugs.
When it comes to knitting, knowing yarn standards makes all the difference. It helps you pick the right needle for projects, use a different yarn than a pattern calls for, and have a finished project match your vision. Hopefully, after reading this article, you can get more from your knitting and have a better understanding of yarn weights.