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 | 14-30 | A |
| 2 | Sport | Fine | 5 | 23-26 | 3.25-3.75 | 250-350 | 12-18 | A |
| 3 | DK | Double Knitting, Light Worsted | 8 | 21-24 | 3.75-4.5 | 200-250 | 11-15 | B |
| 4 | Worsted / Aran | Medium, Afghan | 10 | 16-20 | 4.5-5.5 | 170-220 | 9-12 | C |
| 5 | Bulky | Chunky, Craft | - | 12-15 | 5.5-8 | 100-170 | 6-9 | D |
| 6 | Super Bulky | Super Chunky | - | 7-11 | 8-12.75 | 50-100 | 5-6 | E-F |
| 7 | Jumbo | - | - | ≤6 | 12.75+ | <50 | 1-4 | F |
This table is a guide. CYC, DROPS and WPI do not measure exactly the same thing, so categories can overlap. Yardage is a typical range, not a boundary: DROPS Sky is DK at 380 metres per 100 grams, and DROPS Nepal is aran at 150. DROPS’ group E covers 9 to 11 stitches and group F covers 5 to 8. A yarn at 7 or 8 stitches therefore sits in CYC 6 and in DROPS’ group F. The WPI ranges overlap in CYC’s own guidance, so one number can fall into several categories. 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.
So the category alone does not tell you whether two yarns can replace each other. Nysta compares gauge, fibre, spin and construction and shows how well a substitute yarn matches. With the gauge calculator, you can see for yourself what a difference in gauge means for the finished measurements.
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. The needle size depends on the fabric you want. Open lace patterns are often knitted on larger 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 are used in some naming systems for Fingering and DK weight, while ply elsewhere states the number of plies in the yarn. 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 hold two strands together, they behave as one thicker strand. How much thicker depends on the actual yarns, and you cannot calculate the result by adding yarn weight categories together. Purl Soho and DROPS each provide guidance on combining yarns. You will find both tables in Held together: knitting with multiple strands.
Make a gauge swatch with the strands held together. Wash and dry it the way you will treat the finished piece, then check whether you match the pattern’s gauge and whether the fabric suits the project.
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 in stockinette and look up the value in the CYC table together with the needle size you used. Stitch count alone does not settle the category: DROPS Kid-Silk is lace, but is knitted at 23 stitches on 3.5 mm.
- Supplement with a WPI measurement for a quick indication of the category.
Let Nysta keep track of your stash
When you add a yarn in Nysta, you look it up in the catalogue or scan the ball band. If we know the yarn, we fill in weight category, gauge, yardage and fibre when the information is available, so you don’t have to translate between the systems yourself.
Leftover yarn without a ball band can also be used in Nysta’s pattern suggestions. We help you work out the yarn’s weight category, with guidance on measuring WPI, and suggest known yarns that match your answers. You can also add the yarn manually.
Download Nysta on the App Store and try it free for 7 days.
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 add a known yarn, we fill in weight category, gauge, yardage and fibre when the information is available. If you have leftover yarn without a ball band, the app helps you work out its weight category and other properties.
Add your yarn, and we’ll keep track of weight category, gauge and fibre.
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