When you read a pattern or look at a ball band, you will often see international terms like DK, Worsted, Fingering and Bulky. They all describe the thickness of the yarn, but the system can be confusing to navigate. The international CYC scale overlaps with DROPS’ own yarn group system (A-F), and then there is the WPI method, which you can measure yourself but which rarely tells the full story on its own.
Here is the complete overview of what the different terms mean and how they relate across systems.
Yarn weights and weight categories explained
The Craft Yarn Council (CYC) divides yarn into 8 standardised weight categories from 0 to 7.
| CYC | Name | Other names | Ply | Gauge (sts/10 cm) | Needles (mm) | Yardage (m/100 g) | WPI | DROPS |
|---|---|---|---|---|---|---|---|---|
| 0 | Lace | Laceweight, Cobweb | 2-3 | 33-40 | 1.5-2.25 | 600-800+ | 30-40+ | A |
| 1 | Fingering | Sock, Super Fine, Baby | 4 | 27-32 | 2.25-3.25 | 350-500 | 20-30 | A |
| 2 | Sport | Fine | 5 | 23-26 | 3.25-3.75 | 250-350 | 16-20 | A |
| 3 | DK | Double Knitting, Light Worsted | 8 | 21-24 | 3.75-4.5 | 200-250 | 14-18 | B |
| 4 | Worsted / Aran | Medium, Afghan | 10 | 16-20 | 4.5-5.5 | 170-220 | 11-15 | C |
| 5 | Bulky | Chunky, Craft | - | 12-15 | 5.5-8 | 100-170 | 8-11 | D |
| 6 | Super Bulky | Super Chunky | - | 7-11 | 9-12 | 50-100 | 5-8 | E |
| 7 | Jumbo | - | - | ≤6 | 12.75+ | <50 | <5 | F |
This table is a guide. CYC, DROPS and WPI do not measure exactly the same thing, so categories can overlap. Gauge and a swatch should always determine the final choice.
The categories can overlap slightly. A yarn with a gauge of 21 stitches per 10 cm could technically be classified as either a heavy DK or a light Worsted. In practice, the manufacturer places the yarn in the category that best fits the recommended needle size, but it is not always clear-cut.
A closer look at the main categories
Lace (0) is the finest yarn on the market. It is typically used for delicate lace patterns, lightweight shawls, or as a carry-along strand. It requires patience and fine needles.
Fingering (1) covers classic sock yarn as well as fine wool for light sweaters and cardigans. It is the most popular weight for shawls and finer garments. In the British and Australian tradition, this weight is often called 4-ply.
Sport (2) sits between fingering and DK. It is often used for durable children’s garments and lighter sweaters, but the category is not nearly as common in Scandinavian patterns as it is in American ones.
DK (3) stands for Double Knitting. It is one of the most widely used weight categories in Scandinavian knitting, as it covers the broad middle ground from light to medium projects. Many popular everyday wool yarns belong here.
Worsted / Aran (4) is the classic heavier sweater weight. American designers primarily use the term Worsted, while British and Irish designers prefer Aran. They share the same CYC category, but Worsted typically sits at the lighter end (17-20 sts/10 cm, needles 4.5-5 mm), while Aran belongs at the heavier end (16-18 sts/10 cm, needles 5-5.5 mm).
Bulky (5) is thick yarn for quick projects, including chunky sweaters, hats and home accessories.
Super Bulky (6) and Jumbo (7) are the heaviest categories on the scale. They are primarily used for oversized garments and thick knitted blankets.
What does ply mean?
The ply numbers in the table refer to traditional British standards. Originally, ply counted the number of individual strands twisted together, but today terms like 4-ply and 8-ply function purely as synonyms for Fingering and DK weight respectively. It is a naming convention, not a technical guarantee. A yarn can easily consist of three strands and still have a true DK-weight gauge. Always let the gauge be the deciding factor.
What is WPI (Wraps Per Inch)?
WPI stands for Wraps Per Inch and is a simple home method for determining the thickness of an unknown yarn. You wrap the yarn evenly and without tension around a ruler and count how many wraps fit within one inch (2.54 cm). The result can then be compared against the CYC table.
The method is extremely useful if you have a stash of leftovers without ball bands, but it should be used with caution for three reasons:
- If you stretch the yarn even slightly while wrapping, the strand becomes thinner, and you get an artificially high WPI number.
- The spacing between individual wraps is subjective. Are you packing them tightly, or letting them sit loosely?
- International tables vary. 13 WPI will be classified as Sport in some systems, while others place it as DK or Worsted.
Use WPI for the initial rough sort, and always verify with a gauge swatch.
Knitting with doubled yarn: Holding two strands together
When you choose to knit with two strands held together, the resulting thickness increases substantially. As a general rule of thumb, doubling the strand will move the combined result roughly two categories up on the CYC scale.
Because the different systems were developed independently, the transitions are not always perfectly aligned. This is particularly true for DROPS’ Yarn Group A, which is a broad category covering everything from fine Lace to Fingering and Sport.
Here is an overview of how the most common yarn combinations work out:
| Combination | Typically equivalent to (CYC) | Equivalent (DROPS) |
|---|---|---|
| 2 × Lace (Category 0) | Fingering (Category 1) | Yarn Group A |
| 2 × Fingering (Category 1) | DK / Worsted (Category 3-4) | Yarn Group B / C * |
| 2 × Sport (Category 2) | Worsted (Category 4) | Yarn Group C |
| 2 × DK (Category 3) | Bulky (Category 5) | Yarn Group D |
| 2 × Worsted (Category 4) | Super Bulky (Category 6) | Yarn Group E |
| 3 × Fingering / Sport | Bulky (Category 5) | Yarn Group D |
* Note: Two strands of thin fingering yarn (such as classic sock yarn) typically land as a stable DK weight (Yarn Group B), while two strands of a plumper fingering or sport yarn will reach Worsted (Yarn Group C).
Keep in mind that fibre structure matters too. Two strands of thin silk mohair will fill out more in the finished fabric than the purely mechanical weight suggests, because of the airy fibres. A gauge swatch is therefore the only real guarantee for the correct tension.
How to find the weight of an unknown yarn
- Check the ball band if you still have it. Look for the recommended gauge in stitches per 10 cm.
- Compare with a known reference. Lay a strand of the unknown yarn parallel to a yarn you know the weight of, to visually compare the diameter.
- Knit a gauge swatch. Make the swatch large enough so that you can measure a clean 10 × 10 cm area in the centre, away from the selvedge stitches. Count the stitches and look up the value in the CYC table.
- Supplement with a WPI measurement for a quick indication of the category.
Let Nysta keep track of your stash
Nysta is your shortcut to matching the right yarn with the right patterns. The system starts from your actual stash, and the first step is simply to register your yarn in the app.
Nysta can recognise well-known yarn brands and fill in technical details such as weight category, gauge, yardage and fibre content when data is available. Unknown yarn can be described manually so it can still be used in the app’s matching. If you have an unidentifiable leftover, Nysta guides you through a series of simple visual steps so the app can estimate the yarn’s properties and suggest relevant projects.
Frequently asked questions
What does DK mean? DK is an internationally recognised yarn weight and stands for double knitting. A DK yarn typically has a gauge of 21 to 24 stitches per 10 cm on needles between 3.75 and 4.5 mm, and a length of around 200 to 250 metres per 100 grams. DK is also called light worsted and is used for everything from sweaters to accessories.
What gauge does DK yarn have? DK is an internationally recognised yarn weight, and a DK yarn is typically knitted at 21 to 24 stitches per 10 cm in stockinette on needles between 3.75 and 4.5 mm. On the weight scale, sport sits just below DK and worsted just above, and because the categories border one another, the same yarn can behave like sport or worsted depending on how tightly you knit. So always knit a swatch and let it show the gauge you actually get, rather than the number the manufacturer states.
What is the difference between DK and sport? Both DK and sport are internationally recognised yarn weights, and they sit close together, with sport the slightly thinner of the two. Sport typically has a gauge of 23 to 26 stitches per 10 cm on needles around 3.25 to 3.75 mm, while DK has 21 to 24 stitches on needles around 3.75 to 4.5 mm. The difference is small, and the two categories border one another, so your swatch is the best guide to which one suits your pattern.
What is the difference between DK and fingering? Both DK and fingering are internationally recognised yarn weights, and fingering is considerably thinner than DK and sits two weight categories below it. Fingering typically has a gauge of around 27 to 32 stitches per 10 cm on thin needles of 2.25 to 3.25 mm, where DK has 21 to 24 stitches on needles of 3.75 to 4.5 mm. Two strands of fingering held together often knit up to around DK weight, but it depends on length, fibre and gauge.
What is the difference between DK and Worsted? DK (Double Knitting) and Worsted sit close together, but Worsted is slightly thicker. DK typically has 21-24 stitches per 10 cm, while Worsted sits at 16-20 stitches. In practice they overlap, and many patterns use the terms interchangeably.
What does yarn weight mean? Yarn weight does not refer to how heavy the yarn is on a scale, but to the thickness of the strand. The categories go from 0 (Lace) to 7 (Jumbo) and determine which needle size and gauge the yarn is suited for.
How do I find out what weight category my yarn is? Check the ball band for the recommended needle size and gauge, and compare against the CYC scale. If the ball band is missing, you can do a WPI measurement or knit a quick gauge swatch.
Can Nysta keep track of weight categories for me? Yes. When you register a yarn in Nysta, the app fills in weight category, gauge and fibre content. If you have an unknown leftover, the app guides you through a series of visual steps.
Add your yarn, and we’ll keep track of weight category, gauge and fibre.
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