When learning to knit, crochet or weave, you’ll encounter a term called “yarn weight.” But what is yarn weight and what is its purpose in your project? That’s exactly what I’m going to talk about.
What is Yarn Weight?
In simplest terms, it’s the thickness and density of the yarn. Manufactueres use a categorization system to assign a weight, or label, for each thickness. The most common system used in the Craft Yarn Council Standard Yarn Weight System.
A quick (and relatively subjective way) of determining the weight of your yarn is with a trick called Wraps per Inch or WPI. Take a length of yarn and wrap it snugly (not too tight, not too loose) around a ruler for one inch, making sure there aren’t any gaps between the strand wraps.
The more WPI, the thinner the yarn, and vice versa. It’s not an exact science, but it gets the job done.
Yarn Weight & Gauge
Of course, each manufacturer has slight variations, but you’ll notice on the back of their labels a bit of information on stitch gauge and needle size. These are the “recommended” sizes to achieve a balanced stockinette stitch fabric that is firm enough that your finger can’t poke through, but loose enough to provide drape. It is *not* (I repeat NOT) the “required” needle size and gauge you have to use.
Designers choose yarn weight, needle sizes, and stitch patterns to create the desired drape, look, and feel for their designs. Think of those yarn weight labels as a start point only. Your goal is to know the effect you’re going for, the stitch pattern you’re using, and then you’ll choose a needle size that helps your yarn achieve that look.
So, let’s look at those yarn weights and what they mean.
Lace Weight
Lace weight yarn is the finest and lightest of all yarn weights. With a thread-like texture, this delicate yarn is often used for intricate lace patterns and lightweight projects like shawls, scarves, and delicate garments.
WPI: 30 to 40+
Needle + Stitch Gauge Starting Point: US 000 to 1 needles will put you in the ballpark of 8.25 to 10+ stitches per inch.
Hook + Stitch Gauge Starting Point: Size B1 will put you in the ballpark of 8 to 10.5+ double crochets per inch.
Fingering Weight
Slightly heavier than lace weight, fingering weight yarn is still quite thin. It is often referred to as sock weight yarn (because it’s a great sock weight), but it’s gained popularity over the years for shawls, hats, baby sweaters, and garments.
WPI: 18-30
Needle + Stitch Gauge Starting Point: US 1-3 needles will put you in the ballpark of 6.75-8 stitches per inch.
Hook + Stitch Gauge Starting Point: Sizes B1-E4 will put you in the ballpark of 5.25-8 single crochets per inch.
Sport Weight
This weight falls between fingering and DK (Double Knitting) weight. It’s perfect for a range of projects, like lightweight garments and accessories, thanks to its balance of thickness and lightness. Its moderate weight makes it ideal for creating projects that can be worn year-round.
WPI: 14-18
Needle + Stitch Gauge Starting Point: US 3-5 needles will put you in the ballpark of 5.75-6.5 stitches per inch.
Hook + Stitch Gauge Starting Point: Sizes E4-7 will put you in the ballpark of 4-5 single crochets per inch.
DK Weight
DK-weight yarn, also known as Double Knitting weight, falls between the sport weight and worsted-weight categories. It is a versatile and popular yarn choice, especially in Europe and the United Kingdom. The term “double knitting” can be slightly misleading, as it doesn’t refer to knitting with two strands of yarn. It just means it’s suitable for creating lightweight, double-layered fabrics.
WPI: 12-15
Needle + Stitch Gauge Starting Point: US 5-7 needles will put you in the ballpark of 4.25-6 stitches per inch.
Hook + Stitch Gauge Starting Point: Sizes 7-I9 will put you in the ballpark 3-4.25 single crochets per inch.
Worsted Weight
One of the most popular and widely used yarn weights, worsted-weight yarn is neither too thick nor too thin. Its versatility makes it suitable for a wide range of projects, from sweaters and blankets to scarves and home decor items. If you’re new to crocheting or knitting, use worsted-weight yarn. It shows stitches clearly and helps you finish projects faster.
WPI: 9-12
Needle + Stitch Gauge Starting Point: US 7-9 needles will put you in the ballpark of 4-5 stitches per inch.
Hook + Stitch Gauge Starting Point: Sizes I9-K10 ½ will put you in the ballpark 2.75-3.5 single crochets per inch.
Chunky Weight
Chunky weight yarn is slightly thicker than worsted weight, providing a warm and cozy feel to projects. It is commonly used for knitting or crocheting heavier sweaters, blankets, and outerwear. The added thickness creates a more substantial fabric, making it perfect for cold weather projects.
WPI: 6-9
Needle + Stitch Gauge Starting Point: US 9-11 needles will put you in the ballpark of 3-3.75 stitches per inch.
Hook + Stitch Gauge Starting Point: Sizes K10 ½-M13 will put you in the ballpark 2-2.75 single crochets per inch.
Super Bulky Weight
As the name suggests, super bulky weight yarn is thick and creates projects with significant heft and warmth. It’s great for last-minute gifts or big projects like scarves, cowls, and blankets. Because of its thickness, it may not be suitable for intricate stitch patterns but is perfect for projects that require a quick finish.
WPI: 5-6
Needle + Stitch Gauge Starting Point: US 11-17 needles will put you in the ballpark of 1.75-2.25 stitches per inch.
Hook + Stitch Gauge Starting Point: Sizes M13-Q will put you in the ballpark 1.75-2.25 single crochets per inch.’
Jumbo Weight
Jumbo wight, or as I call it, super-duper-bulky yarn is the heaviest yarn category, and it results in projects with a bold, chunky, and luxurious appearance. This yarn is ideal for creating warm and cozy winter accessories, like chunky beanies, scarves, and cowls. Its thickness often demands the use of large needles or hooks, which makes projects progress even faster.
WPI: 1-4
Needle + Stitch Gauge Starting Point: US 17+ needles will put you in the ballpark of 6 > stitches per inch.
Hook + Stitch Gauge Starting Point: Sizes Q+ will put you in the ballpark 6 > single crochets per inch.
If you use smaller needles for stockinette stitch, the fabric will be denser and larger needles will make it airier. And then, if you change things up with your stitch pattern, you have even more room to play!
Knowing the difference between them is going to help you achieve the desired results in your knitting, crocheting, or weaving projects. It also means you have a starting place when trying to figure out a good yarn substitution.
Each yarn weight has its unique characteristics, making it suitable for specific types of projects. From the delicate lace weight to the super bulky weight, there’s a yarn weight for every creative endeavour.
