What is Yarn Weight
Yarn weight refers to the thickness of yarn and is the most important parameter when selecting material for any project. The weight determines how the finished item will look and behave — from delicate lace to bulky blankets.
The international standard uses the Craft Yarn Council (CYC) system, which divides yarns into 8 categories numbered 0–7. Each category has recommended needles, hooks, and gauge.
Complete Yarn Weight Chart
| Number | Name (EN) | Name (CZ) | Needles (mm) | Hook (mm) | Gauge (4 in) | Typical Use |
|---|---|---|---|---|---|---|
| 0 | Lace | Lace | 1.5–2.25 | 1.5–2.25 | 33–40 sts | Lace, shawls, doilies |
| 1 | Super Fine | Fingering | 2.25–3.25 | 2.25–3.5 | 27–32 sts | Socks, baby clothes |
| 2 | Fine | Sport | 3.25–3.75 | 3.5–4.5 | 23–26 sts | Light sweaters, shawls |
| 3 | Light / DK | DK | 3.75–4.5 | 4.5–5.5 | 21–24 sts | Sweaters, blankets, hats |
| 4 | Medium / Worsted | Worsted | 4.5–5.5 | 5.5–6.5 | 16–20 sts | Universal — sweaters, blankets, amigurumi |
| 5 | Bulky | Bulky | 5.5–8 | 6.5–9 | 12–15 sts | Hats, scarves, quick projects |
| 6 | Super Bulky | Super Bulky | 8–12.75 | 9–16 | 7–11 sts | Heavy blankets, rugs |
| 7 | Jumbo | Jumbo | 12.75+ | 16+ | 6 or fewer | Arm knitting, roving blankets |
How to Determine Yarn Weight
From the label — most branded yarns show the CYC number directly on the label as a symbol (yarn ball with number inside). Also look for recommended needles — you can deduce the weight from these.
Wraps per inch (WPI) — if the label is missing (cone yarn, remnants), wrap the yarn around a ruler for 1 inch (2.54 cm) and count the wraps. 14+ WPI = lace, 12–14 = fingering, 11 = sport, 8–9 = DK, 7 = worsted, 5–6 = bulky.
Gauge swatch — the most accurate method. Knit/crochet a 4×4 inch square with recommended needles and count stitches. Compare with the chart above.
Most Common Weights and Their Uses
Worsted / Medium (Category 4)
The most universal and best-selling weight worldwide. Suitable for everything — sweaters, hats, scarves, blankets, amigurumi, bags. If you're unsure, start with worsted weight. Most beginner patterns use this weight.
DK / Light (Category 3)
Slightly finer than worsted, popular in Europe. More drapey results, suitable for light sweaters, children's clothing, and spring/fall accessories. In stores, you'll find it labeled as "DK" or "light worsted."
Fingering / Super Fine (Category 1)
Fine yarn for socks, lace, and light shawls. Work takes longer, but the result is delicate and elegant. Sock yarn is typically fingering weight with nylon blend for durability.
Bulky / Chunky (Category 5)
Heavy yarn for quick projects. Hat in an evening, scarf over a weekend. Popular with beginners — stitches are large, clearly visible, and work grows quickly. Drawback: finished items are heavier and bulkier.
How to Substitute Yarn Weight
If a pattern calls for a weight you don't have, you can substitute — but you must recalculate gauge. Basic rule: if you use heavier yarn, you need larger needles and the item will be bigger (or you must decrease stitches). Conversely, with finer yarn you need smaller needles and more stitches.
The safest approach is always to knit a gauge swatch with the new yarn and new needles, measure gauge, and recalculate.
