The standard categories
The Craft Yarn Council numbers yarn weights from 0 to 7. Typical knitting gauge in stockinette over 10 cm (4 in): 0 Lace 33–40 stitches; 1 Super Fine (sock, fingering) 27–32; 2 Fine (sport) 23–26; 3 Light (DK, light worsted) 21–24; 4 Medium (worsted, aran) 16–20; 5 Bulky (chunky) 12–15; 6 Super Bulky 7–11; 7 Jumbo 6 or fewer.
Needle ranges
Recommended needles run from 1.5–2.25 mm for lace to 4.5–5.5 mm for medium weight and 12.75 mm and larger for jumbo. These are guidelines; the label of the specific yarn and your own tension decide.
Names vary by market
Terms such as DK, worsted and aran overlap between categories and brands. Metres per 100 g and the recommended gauge on the label are better evidence than the name.
Swatch before substituting
Fibre changes drape and stretch even at the same weight. Make and wash a swatch in the intended stitch and compare gauge before replacing the yarn a pattern specifies.
Practical checklist
- Match total length, not only weight, when substituting.
- Check care instructions before combining yarns.
- Record needle size and gauge with the project.
