What is Yarn Weight?
Yarn comes in all different sizes and has different levels of thickness. To help people who use yarn regularly, such as knitters and crocheters, yarn is classified into categories called “yarn weights.”
Yarn weight is determined by the thickness of the strand of yarn, not by how much the skein (the ball of yarn) weighs.
These yarn weight groups help us select yarn with the right level of thickness for our project.
The yarn weight categories are an effort by The Craft Yarn Council and others to standardize the yarn industry (and crafts that use yarn such as crochet and knitting) around the world with the same label for groups of yarn.
Prior to the Standard Yarn Weight System, what one weight of yarn was called in one country could be completely different in another country.
You may see references to old terms but it’s important to understand and use the new terminology for yarn weights.
Note that yarn weights have nothing to do with “Ply.” According to The Spruce Crafts, the old definition of “ply” is disappearing in favor of the Standard Yarn Weight System.
What are the Different Yarn Weights?
There are eight categories of yarn weights. They range from Size 0, which is the smallest (thinnest) to Size 7, which is the largest (thickest). The eight different yarn weights are:
Yarn Weight Chart
|Yarn Sizes||Yarn Weight Category|
|Size 0||Lace (the smallest)|
|Size 1||Super Fine|
|Size 6||Super Bulky|
|Size 7||Jumbo (the largest)|
The image below shows six of these categories (Size 1 – Size 6).
As you can see in the image above, Size 1 (Super Fine) is extremely thin and each weight gets a little thicker. Size 6 (Super Bulky) is very thick.
Yarn Weights in Action
Now let’s see each of these yarn weights in action and notice their size differences. For this demonstration, I used the exact same crochet hook (H/8 – 5.00 mm) and the exact same number of stitches and rows (10 single crochet stitches across and 10 rows in total).
As you can see in the image above, even though I used the same hook size, the sizes of each swatch is very different. Yarn weight on its own plays a very large role in determining the overall size, look and feel of your item.
Types of Yarn for Crochet
Within the eight yarn weights, there are certain types of yarn that fall into each category. For example, the term “worsted weight” is widely known and used. Worsted weight falls into the Size 4 (Medium) category of yarn weights. Here are the types of yarn in each category:
Types of Yarn Chart
|Yarn Weights||Types of Yarn|
|Size 0 – Lace||Fingering or 10-count crochet thread|
|Size 1 – Super Fine||Sock, Fingering, Baby|
|Size 2 – Fine||Sport, Baby|
|Size 3 – Light||Double knit (dk), Light worsted|
|Size 4 – Medium||Worsted, Afghan, Aran|
|Size 5 – Bulky||Chunky, Craft, Rug|
|Size 6 – Super Bulky||Super Chunky, Roving|
|Size 7 – Jumbo||Ultra, Roving|
Join my email list (it’s free!) and get a printable Crochet Cheat Sheet, which includes a chart of each yarn weight and the type of yarn in each category.
Yarn Weights & Crochet Hook Size
Each yarn weight has recommended crochet hook sizes. These are the most commonly used hooks for each category.
Note: it is absolutely okay to use a hook that is outside of the range provided for the size of yarn. For example, in my Simple Baby Blanket crochet pattern, I used a K/10.5 (6.50 mm) hook and size 3 (light/dk) yarn, even though the range for this size yarn is G/6 (4.00 mm) to I/9 (5.50 mm). Mixing and matching different size yarns with different size crochet hooks allow you to achieve unique designs.
Learn more: Crochet Hook Sizes & Chart – A Complete Guide
Yarn Weight & Gauge
To help ensure your design turns out to be the same size as what’s intended, it is recommended that you always make a gauge swatch and check your gauge. You can learn more and how to do this in my step-by-step guide to gauge.
Yarn weight plays a major role in determining the gauge, especially if you are going to use a different yarn weight than what was recommended in the pattern.
There is a recommended gauge for each yarn category but these are only guidelines based on the most common gauge for each yarn weight. Is important that you check your gauge for each project.
Yarn Weight Chart
This yarn weight chart includes the yarn size (the yarn weight category), the types of yarn in each category, the recommended hook sizes based on what is most commonly used and the average gauge for that yarn weight group.
|Yarn Weight||Yarn Types||Hook Sizes*||Gauge**|
|Size 0 – Lace||Fingering or 10-count crochet thread||B/1 (2.25 mm) or Steel Hooks||4″ = 32-42 dc|
|Size 1 – Fine||Sock, Fingering, Baby||B/1 (2.25 mm) to E/4 (3.5 mm)||4″ = 21-32 sc|
|Size 2 – Super Fine||Sport, Baby||E/4 (3.5 mm) to 7 (4.5 mm)||4″ = 16-20 sc|
|Size 3 – Light||Double knit (dk), Light worsted||G/6 (4.00 mm) to I/9 (5.5 mm)||4″ = 12-17 sc|
|Size 4 – Medium||Worsted, Afghan, Aran||H/8 (5 mm) to K/10.5 (6.5 mm)||4″ = 11-14 sc|
|Size 5 – Bulky||Chunky, Craft, Rug||K/10.5 (6.5 mm) to M/13 (9 mm)||4″ = 8-11 sc|
|Size 6 – Super Bulky||Super Chunky, Roving||M/13 (9 mm) to Q (15 mm)||4″ = 7-9 sc|
|Size 7 – Jumbo||Ultra, Roving||Q (15 mm) or larger||4″ = 6 sc or less|
*The hook sizes list here are only the most commonly used and it is not absolutely necessary to use a hook within the range provided for each type of yarn
**The gauges listed are only guidelines. It’s important to check your gauge for each project.
Printable Yarn Weight Chart
Here is a chart you can print, save to your files or save to Pinterest. If you are on a computer, right-click and choose “save as” and then you can print the image. If you are on a mobile device, hold down on the image and then click “save to photos.” Or hover over it and click the Pinterest save button.
Yarn Sizes in Detail
Let’s explore each of these yarn sizes in more detail. Remember that the hooks and gauge are only guidelines.
Size 0 – Lace
- Types: Fingering 10-count crochet thread
- Hooks: B/1 (2.25 mm) or Steel Hooks
- Gauge: 4″ = 32-42 dc
Size 0 yarn is the lightest (thinnest) weight of yarn. Lace yarn usually requires you to use the smallest crochet hook (B/1 (2.25 mm) or special Steel crochet hooks, which are used for this thin thread-like yarn. Lace yarn is very delicate and not recommended for beginners. Lace yarn is used to make lacy shawls, scarves and wraps.
Size 1 – Super Fine
- Types: Fingering, Sock & Baby
- Hooks: B/1 (2.25 mm) to E/4 (3.5 mm)
- Gauge: 4″ = 21-32 sc
There isn’t a huge difference between Size 0 (Lace) and Size 1 (Super Fine). Both are used for lace designs such as shawls and scarves and are very delicate. While there are crochet patterns for Size 1 yarn, it is more frequently used in knitting, especially socks.
Size 2 – Fine
- Types: Sport, Baby
- Hooks: E/4 (3.5 mm) to 7 (4.5 mm)
- Gauge: 4″ = 16-20 sc
While there are crochet patterns for Sizes 0 and 1, Size 2 (Fine) is more popular. You’ll frequently see this yarn used in making shawls like this Easy Triangle Shawl pattern or other accessories like this Easy Bandana pattern. The lace designs you can make size 2 are not as delicate as using thinner yarn making your finished items easier to care for and work with.
Size 3 – Light
- Types: Double knit (DK), Light worsted
- Hooks: G/6 (4 mm) to I/9 (5.5 mm)
- Gauge 4″ = 12-17 sc
Size 3 (Light) is a very popular yarn weight, especially for baby blankets as it often makes lovely, flowing, airy blankets that are cozy but not too thick – ideal for a baby. Some baby blanket patterns using size 3 include this Simple Baby Blanket, Adorable Baby Blankets and Gender Neutral Baby Blanket. You can achieve wonderful textures using this yarn. It’s also quite easy to use, making it okay for beginners. Size 3 is often used in Amigurumi (small, stuffed creatures) and making lightweight garments.
Size 4 – Medium
- Types: Worsted, Afgan, Aran
- Hooks: H/8 (5 mm) to K/10.5 (6.5 mm)
- Gauge: 4″ = 11-14 sc
Size 4 (Medium) is the most widely used yarn weight. It’s great for beginners as you can easily see the stitches you are making. You can make almost anything with Size 4 yarn such as scarves, sweaters, hats, accessories and blankets plus much much more.
The thickness is perfect for making items for cold weather. Yarn in this category can vary in thickness quite drastically. Some brands classify the yarn as size 4 even though it looks and feels more like size 3. On the other hand, there is some really thick yarn classified as size 4. It’s important to check your gauge, even if the size isn’t essential to see if the look and feel of your work is how it’s intended to be.
Here are some easy patterns made with Size 4 yarn: Easy Cowl, Easy Placemat, Classic Baby Blanket.
Size 5 – Bulky
- Types: Chunky, Craft, Rug
- Hooks: K/10.5 (6.5 mm) to M/13 (9 mm)
- Gauge: 4″ = 8-11 sc
Size 5 (Bulky) yarn is great to work with as you can complete projects quite quickly like this 3-hour, 1-skein easy Chunky Scarf pattern. There’s an extensive variety of patterns that use Size 5 yarn blankets, scarves, hats, rugs and many more. Size 5 is great for colorwork, as the thick size of the strands hides the unused color such as in this Music Notes Pillow Cover.
Size 6 – Super Bulky
- Types: Super chunky, Roving
- Hooks: M/13 (9 mm) to Q (15 mm)
- Gauge: 4″ = 7-9 sc
Size 6 (Super Bulky) is great for making fast baskets, scarves and rugs because it works up so quickly. You can also make super cozy blankets that are fantastic for the wintertime to snuggle up under, like this Paw Print Blanket.
Size 7 – Jumbo
- Types: Ultra, Roving
- Hooks: 4″ = 7-9 sc
- Gauge: 4″ = 6 sc or less
Size 7 (Jumbo) yarn is the thickest yarn and is used commonly used to make ultra-thick and heavy blankets. There are also patterns for pillows, mats and home decor items using this size. It’s also frequently used in finger crocheting.
How to Determine Yarn Weight
If your yarn is missing its label and you aren’t sure what the yarn weight is, you can easily find out what it’s “wraps per inch” or WPI. Each yarn category has a WPI range based on the findings of industry experts. By wrapping your yarn around an object (like a pencil) and measuring how many wraps are in one inch, you can then compare it to the WPI chart and determine your yarn’s weight.
Here’s how to determine yarn weight by wraps per inch (WPI) :
- Get a pencil and a measuring tape/ruler
- Wrap your yarn around a pencil a couple of inches times. Keep an even tension – not too tight and not too loose. Ensure the strands are touching but not overlapping.
- Hold the measuring tape or ruler parallel to the pencil and count the number of wraps in a 1″ area.
- Compare your number of wraps to the chart below and see which range your number belongs to. That’s your yarn’s weight.
Note that WPI is subjective and how tightly you wrap your yarn could impact the results. But it’s a helpful starting point. Remember to always check your gauge.
Wraps Per Inch for Each Yarn Weight
|Wraps Per Inch (WPI)||Yarn Weight|
|30 – 40+||Size 0 (Lace)|
|14 – 30||Size 1 (Super Fine)|
|12 – 18||Size 2 (Fine)|
|11 – 15||Size 3 (Light)|
|9 – 12||Size 4 (Medium)|
|6 – 9||Size 5 (Bulky)|
|5 – 6||Size 6 (Super Bulky)|
|1 – 4||Size 7 (Jumbo)|
It can be frustrating when a certain yarn gets discontinued or if the recommended yarn for the pattern is not available in your region. To find a similar yarn, you can use this handy Yarn Substitution Tool. Simply type in the name of the discontinued or recommended yarn and it will show you suggestions for similar yarn based on the texture, fibers, qualities, gauge, size of the skein and colors.
Yarn Held Together
Some patterns call for two (or more) strands of yarn to be held together. What this means is to separate the yarn into two (or more) balls/skeins (or use multiple original skeins) and treat them as one strand of yarn.
Holding multiple strands together and crocheting normally creates a textured, dense and squishy fabric.
My Tote Bag crochet pattern uses two strands of yarn held together so that the bag straps don’t stretch and the bag is strong.
Yarn Held Double
While there could be times the designer recommends three or more strands, it’s most common for two strands to be worked together. This is called Yarn Held Double.
When you hold two strands together, it changes the thickness thus changing the size/category of the yarn.
Yarn Held Together Chart
Here is a chart of how to get a thicker yarn by combining two strands of thinner yarn. Note that only the most common yarn is referenced here as it’s rare that Size 0, Size 6 and Size 7 are held together.
|Two Strands Held Together||= One Strand of This Weight|
|Size 1 (Super Fine)||1 Strand of Size 2 (Fine)|
|Size 2 (Fine)||Size 3 (Light)|
|Size 3 (Light)||Size 4 (Medium)|
|Size 4 (Medium)||Size 5 (Bulky)|
|Size 5 (Bulky)||Size 6 (Super Bulky)|
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Using Yarn Weight for Yarn Length Calculations
The categories of yarn weights are determined by thickness (the diameter) of the strand of yarn and not the weight of the skein (ball of yarn).
However, measuring the weight of your skein of yarn can help with several calculations such as how much yarn is left in a skein.
First, we need to understand the skein’s length and weight. Each yarn label will have its length listed, usually in yards and/or meters. When a skein says 285 yds (260 m) for example, that means that if you unwound all the yarn, the total length would the 285 yards or 260 meters.
The other measurement the yarn label will state is its weight. If the yarn label says that a skein is 4.5 oz, it means that the ball of yarn when weighed on a scale should be 4.5 ounces. Using the metric system, the same ball of yarn in this example weighs 127.5 g.
One note about skein weight is that there are slight discrepancies between the weight of the label and the actual weight of the skein. If you purchased 10 skeins of the same yarn, each could weigh a little less or a little more than what is stated on the label by approx. 10 g.
Yarn Weight Calculations
It’s quite easy to tell how much yarn is in a full skein because it’s stated on the label. But what about once the skein has been used? Unless you want to unwind it and measure it, you’ll want to use a kitchen scale and do some calculations to determine how much yarn is left in the skein.
A digital kitchen scale is a great addition to your crochet supplies. I use mine every day to weigh skeins. They are quite small and relatively inexpensive like this recommended Digital Scale.
To determine how much yarn is left in your skein, weigh the skein on a digital scale. Note the weight in grams. Have your yarn label handy and enter your numbers into this yarn weight calculator.
Frequently Asked Questions about Yarn Weights
What is the DK Weight Number?
DK or Double Knit is a number 3 yarn, meaning that it belongs to the Size 3 (Light) yarn weight category as per the Standard Yarn Weight System. Dk is a lightweight yarn that is quite popular and is often used to make crochet baby blankets.
What is the Size 3 Yarn Weight?
Size 3 yarn weight is a category within the Standard Yarn Weight System called Light. The types of yarn that belong to Size 3 (light) are double knit (dk) and light worsted. Size 3 (light) yarn is a lightweight yarn that comes in a wide variety of colors and is often used for light garments and baby blankets.
What is the Sport Weight Yarn Number?
Sport weight yarn is a number 2 yarn, meaning that it belongs to the Size 2 (Fine) yarn weight category as per the Standard Yarn Weight System. Sport weight yarn and other Size 2 (Fine) yarn is often used in knitting to make socks and in crochet to make larger lace items such as shawls and scarves.
What is the Worsted Weight Yarn Number?
Worsted weight yarn is a number 4 yarn, meaning that it belongs to the Size 4 (Medium) yarn weight category as per the Standard Yarn Weight System. This category includes worsted weight, afghan and Aran. Size 4 (Medium/Worsted Weight) yarn is the most popular and widely used yarn in knitting and crochet.
What is the Size 2 Yarn Weight?
Size 2 yarn weight is a category within the Standard Yarn Weight System called Fine. The types of yarn that belong to Size 2 (fine) are sport and baby. Size 2 (fine) yarn is a thin, very lightweight yarn that is often used to make scarves, shawls and larger lace designs.
I hope this guide to yarn weights has helped you find the right yarn to use for your project!
UP NEXT: Step by Step Guide to Gauge
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