Every knitting or crochet pattern names a yarn weight — "DK," "worsted," "aran," "chunky" — and those words decide almost everything about the project: the needle size, how many stitches fit in a centimeter, how much yarn you'll need and how the finished fabric drapes. The confusing part is that the same thickness has different names in different countries. This guide translates them, and shows how to substitute a yarn safely when the one in the pattern isn't available.
What "weight" actually means
Yarn weight means thickness, not how heavy a ball is. A 100 g ball of fine yarn and a 100 g ball of bulky yarn weigh the same, but the fine one is several times longer. That's why length per weight (meters per 100 g) is the most useful number on a yarn label.
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The standard weight system
The Craft Yarn Council's numbered system (0 to 7) is printed on many labels. The ranges below are typical guides, not rules — always follow the pattern's gauge.
| # | Common names | Typical knitting needle | Typical crochet hook |
|---|---|---|---|
| 0 | Lace, cobweb | 1.5–2.25 mm | 1.4–2.25 mm (steel) |
| 1 | Super fine, fingering, sock, 4-ply | 2.25–3.25 mm | 2.25–3.5 mm |
| 2 | Fine, sport, baby | 3.25–3.75 mm | 3.5–4.5 mm |
| 3 | Light, DK (double knitting), light worsted | 3.75–4.5 mm | 4.5–5.5 mm |
| 4 | Medium, worsted, aran, afghan | 4.5–5.5 mm | 5.5–6.5 mm |
| 5 | Bulky, chunky | 5.5–8 mm | 6.5–9 mm |
| 6 | Super bulky, super chunky | 8–12.75 mm | 9–15 mm |
| 7 | Jumbo | 12.75 mm and up | 15 mm and up |
Names that trip people up
- "4-ply" isn't weight 4. In the UK and Australia, 4-ply means fingering (weight 1). Ply originally counted strands, but today it's just a name.
- Worsted vs aran. Both sit in category 4, but aran is usually a little thicker. A worsted pattern knit in aran comes out slightly larger.
- "8-ply" in Australia and New Zealand is roughly DK.
- "Sock yarn" describes use more than weight — it's usually fingering, often with nylon added for durability.
Wraps per inch: identify a yarn with no label
Wrap the yarn around a ruler or pencil, side by side without gaps or stretching, for one inch (2.5 cm), and count the wraps. Roughly: 18+ wraps is lace to fingering, 12–14 is DK, 9–11 is worsted/aran, 7–8 is chunky, and 6 or fewer is super bulky. It's an estimate, but it's enough to put a mystery ball in the right category.
How to substitute yarn in a pattern
- Match the weight category first — DK for DK.
- Compare meters per 100 g. Two DK yarns can differ a lot. If the pattern yarn has 225 m per 100 g, look for something within about 10% (roughly 200–250 m). Closer means more similar thickness.
- Work out quantity by length, not balls. Multiply the pattern's ball count by its meters per ball, then divide by your yarn's meters per ball and round up. Buy one extra if the dye lot matters.
- Consider fiber. Cotton and linen have no stretch and drape heavily; wool is elastic and forgiving; acrylic is easy-care but less warm; alpaca grows longer when worn. A sweater designed for springy wool can sag in cotton even at the same gauge.
- Swatch. Knit or crochet a 15 × 15 cm square in pattern stitch, wash and dry it the way you'll treat the finished item, then measure. More stitches than the pattern says: go up a needle size. Fewer: go down.
Choosing a weight for a first project
Worsted, aran or DK in a smooth, light-colored wool or wool blend is the easiest to learn with: stitches are easy to see, mistakes are easy to undo, and projects grow at a satisfying pace. Very fine yarn takes a long time; very bulky yarn hides stitch structure and can be tiring on the hands.
Where Hobbii fits
Hobbii, a yarn company founded in Copenhagen in 2015, makes its own yarn and sells it direct, across weights from lace to bulky and fibers including cotton, acrylic, alpaca, mohair, silk and wool blends. It publishes more than 350 designer patterns, many of them free, written for those yarns. Following one of its patterns with the yarn it was designed for removes the substitution step entirely, which is useful for a first project. The company has offered returns up to three months after purchase; check the current terms on its site before buying extra.
Reading a yarn label
Most of what you need for a substitution is printed on the ball band. Look for:
- Weight symbol or name — the numbered category or a name like DK or aran.
- Length and weight — for example "50 g / 125 m". Divide to compare yarns on the same basis (meters per 100 g).
- Fiber content — percentages matter: a 70/30 wool-nylon sock yarn behaves differently from pure merino.
- Suggested gauge and needle size — the manufacturer's starting point, not a promise for your tension.
- Care symbols — machine-washable ("superwash") wool and hand-wash-only wool can't be mixed in one garment without trouble.
- Color and dye lot numbers — buy all the yarn for one project from the same lot if you can.
Quick glossary
- Gauge (tension): stitches and rows per 10 cm — the number that decides finished size.
- Dye lot: the batch a yarn was dyed in; colors can vary between lots.
- Held double: two strands worked together, roughly jumping one or two weight categories.
- Drape: how the fabric hangs; looser gauge and plant fibers drape more.
Conclusion
Yarn weight names vary by country, but the system underneath is simple: thickness, measured best by meters per 100 g. Match the weight category, keep the length within about 10%, think about how the fiber behaves, and always swatch before committing to a whole project. Once those habits are in place, you can substitute almost any yarn with confidence — or skip the guesswork entirely by pairing a pattern with the yarn it was written for.
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If you're ready to buy, Hobbii is worth checking — they currently have 10% off + free shipping with code HAPPY10 live right now.
If you're ready to buy, Hobbii is worth checking — they currently have 10% off + free shipping with code HAPPY10 live right now.
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