What am I supposed to do? Get out a scale to figure out what “weight” of yarn I’m using? Whoever got to decide how to describe yarn in this way needs a good talking to. Why not just like – really thick, thick, medium thick, thin, thinner and thinnest? That makes more sense to my brain. So, in this here article, you will finally have yarn weights explained + a quick reference guide so you’ll never have to wonder again!

If you’re just here for the free downloadable Yarn Weights Quick Reference Guide, you can find it here! You can download it to your computer and/or print it out and it’s yours forever.

Now, understanding yarn weight is super important no matter what kind of fiber art you’re into. Here, we crochet, but whether you knit or crochet or whatnot, you’ll want to know this stuff. Here are the main reasons why understanding yarn weight is important:

1. If you’re following a pattern and you use the wrong yarn weight, you’re finished product will be ALL WRONG.
2. You need to understand how the size of your hook matched with the weight of your yarn will affect your finished product
3. Because understanding yarn weight expands the knowledge in your brain and makes you cooler

So, in this article, we will cover the following:

1. What is yarn weight?
2. Common names for any given yarn weight
3. The recommended hook size to use with any given yarn weight (emphasis on RECOMMENDED)
4. How to determine the weight of your yarn if it’s missing the label
5. How to create the weight you need with the yarn you have
6. A downloadable quick reference guide that summarizes all of the above

So let’s get to it!

What is yarn weight?

Yarn weight is simply the thickness of the yarn. The thicker the yarn, the “heavier” it is. There are 8 standard yarn weights which are specified with numbers – zero through seven – with zero being the thinnest/lightest and seven being the thickest/heaviest. They also have common names. For example, size four (4) is called “Medium” and is commonly named “worsted” weight. Here are the weights with their common names:

0: Lace (aka – thread, light, fingering)
1: Super Fine (aka – fingering, sock, baby)
2: Fine (aka – sport, baby)
3: Light (aka – DK, light worsted)
4: Medium (aka – worsted, aran, afghan)
5: Bulky (aka – chunky, rug, craft)
6: Super Bulky (aka – roving, bulky)
7: Jumbo (aka – roving)

I love this depiction from the Craft Yarn Council (full photo credit to them!) which illustrates the yarn weights side by side:

Recommended hook sizes to use with any given yarn weight

When you approach a pattern, the designer will indicate which size of yarn to use and which size of hook to use. And if you want the pattern to turn out just like the pattern specifies, it is extremely important to follow their instruction on these sizes. If you don’t, your finished product will be a totally different size because the hook dictates the size of the stitches and the yarn weight will affect the bulk of your finished product. So, while we are having yarn weights explained, let’s also explore how to match those yarn weights with the appropriate hook size.

There is a standard given which recommends how to match the yarn weight to the hook size. This standard BY NO MEANS is the only “right” way to do it. For example, it is recommended that you use a size 5.50 mm hook when using yarn weight 4 (Medium/Worsted). However, if you want more breathability, drape, flexibility, gaps, etc, in your finished product, you can use a larger hook with weight 4, which will make your stitches larger. Alternatively, it is common (and almost guaranteed) that when making Amigurumi, you use at least one size smaller crochet hook than the standard recommends to ensure you have a super tight stitch with no gaps for stuffing to show through.

Here is what the standard match recommends:

0: Lace (aka – thread, light, fingering) / crochet hook size 0.75-2.00 mm
1: Super Fine (aka – fingering, sock, baby) / crochet hook size 2.25-3.50 mm (US B-1 to E-4)
2: Fine (aka – sport, baby) / crochet hook size 3.50mm-4.50mm (US E-4 to 7)
3: Light (aka – DK, light worsted) / crochet hook size 4.50mm-5.50mm (US 7 to I-9)
4: Medium (aka – worsted, aran, afghan) / crochet hook size 5.50mm-6.50mm (I-9 to K-10.5)
5: Bulky (aka – chunky, rug, craft) / crochet hook size 6.5mm-9.0mm (K-10.5 to N-13)
6: Super Bulky (aka – roving, bulky) / crochet hook size 9.0mm-15mm (US N-13 to P,Q)
7: Jumbo (aka – roving) / crochet hook size 15 mm+ (US P,Q to Y)

How to determine the weight of your yarn if it’s missing the label – WPI

If you pick up a great bag of yarn at a second hand store or garage sale (score!), there’s a good chance it will be missing the original ball band label. Or, if you toss the label on a skein but don’t use it up, you’re going to want to know what weight it is the next time you go to use it. Don’t fret! There’s a way to accurately determine what weigh it is. Its called WRAPS PER INCH, or WPI.

Each weight will consistently give the same number of WPI, when wrapping the yarn around any given tool. I use a ruler because I can quickly see when I’ve filled up an inch – but you can use any tool (hook, pencil, etc). Just make sure you can measure an accurate inch. There is a small range for each because not everyone will wrap with the exact same tension. Just hold your yarn averagely loose and wrap with an average tension – not too loose, not too tight. Wrap the yarn around your tool, allowing the strands to touch each other, but don’t overlap them or squish them together.

Here’s the number of wraps each weight will make:

0 Lace: 30+ WPI
1 Super Fine: 19-30 WPI
2 Fine: 15-18 WPI
3 Light: 12-14 WPI
4 Medium: 9-11 WPI
5 Bulky: 7-8 WPI
6 Super Bulky: 5-6 WPI
7 Jumbo: 1-4 WPI

This photo shows an example of a measurement I took of an unlabeled yarn ball I have. There are 10 wraps per the inch. So, kids, what yarn weight do we have? That’s correct – Medium/Worsted!

How to create the weight you need with the yarn you have (if you don’t have what you need)

Just to top off this Yarn Weights Explained article for fun, here’s a quick tip on a way you can create the weight you need if you don’t have it on hand, but have LOTS of another weight on hand. In short – double it up! This isn’t an exact science, so I definitely recommend making a gauge swatch based on the results your pattern is calling for. But, in general, here are the acceptable recipes for making a heavier weight yarn, by doubling up on a lighter weight yarn:

• 2 strands of lace (0) = 1 strand of super fine (1)
• 2 strands of super fine (1) = 1 strand of fine (2)
• 2 strands of fine (2) = 1 strand of light (3)
• 2 strands of light (3) = 1 strand of medium (4)
• 2 strands of medium (4) = 1 strand of bulky (5)
• 2 strands of bulky (5) = 1 strand of super bulky (6)

Yarn Weight Quick Reference Guide

To sum it all up, I’ve created this free downloadable Yarn Weight Quick Reference Guide which includes all the info you will need to be a yarn weight expert! Just click on the image below to be taken to the access page for my Free Resource Library. Enter in your email address and you’ll have instant access to not only this guide, but many more guides, crochet patterns and other resources!

Please let me know in the comments if this was helpful, and what other resources you’d love to have!