The Essential Guide to Yarn Weight
everything you need to know about yarn weight

The Essential Guide to Yarn Weight

Welcome to the Ultimate Guide to Yarn Weight!

This guide is designed to cover all aspects of yarn weight like why it’s important to understand, how yarn is categorized, and we’ll break down each weight to help answer the questions you have (or will have) about yarn weights.

Combine this information with our guide on yarn substitution and you’ll be well on your way to making a confident decision of which yarn to use in your project.

So why is it important to understand yarn weight anyway?

If you don’t have the exact yarn a pattern calls for and you can’t get it, you have a difficult decision to make. Either substitute with a yarn you have or that you can get, which can be a risky choice (the sizing may be off after you did all that work) or you can forgo the idea of making the project at all. No fun.

Since we both agree the first option is the best in most cases, understanding the yarn weight system is the first step to making that project with a yarn have or have access to.

Yarn weight is a quality that won’t change and we can use it as a starting point when making a pattern yarn substitution.

Publishers, manufacturers and members of The Craft Yarn Council worked together to set up a system to bring uniformity to the yarn industry making it easier to prepare consumer-friendly patterns.

What is the yarn weight system?

Yarn weight is categorized using a standard system of numbers, symbols and names. These standards (among others) were put in place by The Craft Yarn Council, an organization that represents the leading yarn companies in the yarn industry including Bernat, Caron, Lily Yarns, Lion Brand, Love Crafts, Patons and Red Heart.

This system ensures all yarns produced by these companies will include one of the seven recognized yarn weights on the label.

Source: Craft Yarn Council’s

All yarns manufactured from Bernat, Caron, Lily Yarns, Lion Brand, Love Crafts, Patons and Red Heart are assigned a weight category and have the coordinating weight icon printed on the label.

These brands are yarn members of the Craft Yarn Council and have therefore adopted these guidelines. However, that is not the case for every yarn you may come across. Many yarns available in parts of Europe use different terminology to categorize weight.

This raises the question, what yarn weight is aran? Or, what yarn weight is DK? Or, what yarn weight is 4 ply? We could go on and on.

The fundamental truth remains the same.

Yarn weight is a quality of the yarn that won’t change. However, the terms used to describe it do and it’s typically based on region.

Just like you would refer to a Thesaurus for a list of words that mean the same thing, refer to this yarn weight chart when you hear a weight term you’re less familiar with.

Craft Yarn CouncilUS TermUK TermAUS Term
(0) LaceLace1 ply2 ply
(1) Super FineFingering2 ply3 ply
(2) FineSport4 ply5 ply
(3) LightDKDK8 ply
(4) MediumWorstedAran10 ply
(5) BulkyBulkyChunky12 ply
(6) Super BulkySuper BulkySuper Chunky14 ply
(7) JumboJumbo

The terms in each row are synonymous. Although it might prove useful to be familiar with all terms, it’s not necessary for your success. Adopt one column as the terms you’re most familiar with and refer back to this conversion chart if the need arises.

Here at B.Hooked you’ll find Craft Yarn Council standard terms used for yarn weights in patterns and all resources where yarn weight is mentioned.

Are some yarn weights better for certain projects?

While some fiber contents prove better for certain projects, the answer isn’t as straight forward when talking about yarn weight. The answer here is very subjective.

The more you experiment with different yarn weights and finish projects of all shapes and sizes, you’ll find yourself more fond of some and not for others.

Consider these questions when deciding what yarn weight is best for your project.

  1. How big is the project going to be?
  2. How much time do you have to work on it?
  3. Does it need to be durable or flexible?

It goes without saying, thinner yarn produces smaller stitches and projects will take more time to complete. Thicker yarn produces bigger stitches and projects will take less time to complete.

So light yarn wouldn’t be a practical choice for a large blanket you only have a couple weeks to finish because the stitches will be significantly smaller than a medium or bulky weight yarn.

This brings us to the point of durability vs flexibility. Generally speaking, thinner yarn when knit or crocheted will produce a lighter, more flexible fabric while thicker yarn will produce a more durable, rigid fabric.

However, additional factors like hook/needle size and stitch pattern play a part in how rigid or flexible a fabric will be so don’t base this on yarn weight alone.

Here are a few ideas to get you started

(0) Lace

Shawls; layering garments

(1) Super Fine

Doilies; Socks; Shawls

(2) Fine

Sweaters; light scarves

(3) Fine

Baby blankets & clothing;

(4) Medium

Hats; Scarves; Bags

(5) Bulky


(6) Super Bulky

Pillows; Blankets

(7) Jumbo


additional resources

Standard Yarn Weights & Project Inspiration on B.Hooked TV