Knitting 101: Understanding Yarn Weights

When starting a new project, picking out yarn is equal parts exciting and perplexing. On one hand there is an entire LYS full of beautiful and alluring yarns to choose from, but on the other hand how do you pick the right one? There are many factors to consider about a fiber, but its weight is a logical first place to start.

What Is Yarn Weight?

Yarn weight refers to a yarn’s thickness, which can vary from fine to bulky. In theory, thin yarns produce more stitches per inch in terms of gauge and thicker yarns produce fewer per inch (we could talk about gauge forever, so more on that later). The Craft Yarn Council (CYC) has taken this into consideration and has established the Standard Yarn Weight System, which identifies 7 categories of yarn weight. The categories are numbered 0-6 (indicated by the icons below), where 0 is Lace Weight and 6 is Super Bulky. The CYC goes on to establish recommended standards within each weight category in terms of recommended gauge and needle size, which you can see in the chart below. These recommendations are put in place to help eliminate some of the guesswork when it comes to picking yarn. But, if only it was that easy..

Despite the CYC’s efforts, the Standard Yarn Weight System is not uniformly recognized within the needlecraft industry, and its information (and icon) is not required to be put on a ball band or referred to in a pattern. Instead, some patterns will list yarn weight by ply* and others will call it by its common name (like Worsted or DK). What a LYS might call “sport weight,” the CYC could call “fine.” This inconsistency makes picking the perfect yarn for a project almost as time consuming as knitting a fair isle sweater.

So what’s a knitter to do? We recommend becoming familiar with the Standard Yarn Weight System (or simply bookmark this blog). While the chart is only a recommendation of gauge and needle size, it will allow you to cross reference the information you have to narrow down your options and determine what yarn is right for the job. And remember, the “right yarn for the job” always means what yarn and needle combo helps you knit the correct gauge called for by the pattern.


Below are the CYC’s icons (with Standard Yarn Weight System name and number delineation), common name, recommended gauge over 4″ stockinette stitch, recommended needle size, and WPI or Wraps Per Inch (see more info about WPI below) based on Ravelry standards.

LACE WEIGHT aka Fingering, Crochet Thread

Typically used for delicate items, especially those with lace work, like shawls and doilies.

Recommended Gauge: 33-40 sts over 4″ stockinette stitch

Recommended Needle Size: US 0-1

WPI: 20+


Typically used for lightweight items like baby wear, socks, hats, and mittens.

Recommended Gauge: 27-32 sts over 4″ stockinette stitch

Recommended Needle Size: US 1-3

WPI: 14


Typically used for summer knits, baby wear, and lightweight clothing items.

Recommended Gauge: 23-26 sts over 4″ stockinette stitch

Recommended Needle Size: US 3-5

WPI: 12

DK WEIGHT aka Light Worsted, Double Knit

Typically used for baby items, hats, shawls, and clothing items.

Recommended Gauge: 21-24 sts over 4″ stockinette stitch

Recommended Needle Size: US 5-7

WPI: 11


Typically used for quick knit garments, like sweaters and hats

Recommended Gauge: 16-20 sts over 4″ stockinette stitch

Recommended Needle Size: US 7-9

WPI: 9


Recommended Gauge: 12-15Typically used for heavy garments like hats, sweaters, and mittens.

Recommended Needle Size: US 9-11 sts over 4″ stockinette stitch

WPI: 7

BULKY aka Roving

Typically used for super fast knit scarves and accessories.

Recommended Gauge: 6-11 sts over 4″ stockinette stitch

Recommended Needle Size: US 11+

WPI: 5-6




Many patterns will reference the ply of a yarn, but unless you’re a fiber-phile, there is really no need to pay too much attention to this “weight” category. Back in the early days of knitting, when yarn was limited to just wool, categorizing yarn by ply made sense. Each strand, or ply, used was approximately the same size, so a 2-ply yarn was consistently a delicate yarn, while an 8-ply made for a more bulky knit. Now that our fiber options have expanded (hooray for bamboo, cotton, and silk!), the ply categorial system is not always accurate; a 2-ply bulky and 2-ply worsted are drastically different in weight.


Wraps per inch is a more modern method on determining yarn weight. You won’t typically see WPI on a pattern or ball band, but it is a handy method of determining weight for those skeins in your stash that don’t have a ball band. To determine WPI, wrap your yarn around a ruler for the length of one inch. Make sure your yarn is not wrapped too tightly and that there are no spaces in between each “wrap.” Then, count how many time you “wraps” you made around the ruler. Then voila! You have approximate yarn weight!

Ounces and Grams

Most ball bands will list ounces and grams. For purposes of yarn weight, this information is useless. After much research it seems that this “measurement” is an early UK method of determining yardage. One chart we found explains that 1 gram of lace weight yarn translates to 8.8 yards and 1grams of worsted weight translates to 2.2 yards. Again, if you find a skein without a ball band, this measurement will help you determine yardage, not yarn weight.


Yarn weight is important to understand, but all you know about it is trumped by gauge. In the end, it is the yarn and needle combo that help you achieve gauge that are the right tools for your project. And as promised, stay tuned for more information on gauge.

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One Thought to “Knitting 101: Understanding Yarn Weights”

  1. Sonya

    This is great information to know! Thank you for informing us! I have been confused lately by the inconsistencies in the yarn weight label, and this explains it! 🙂

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