Crochet yarn weights, lace to jumbo
Every weight from lace to jumbo: the hook to pair it with, the gauge to expect over four inches, the UK name, and what each one is used for.
The ball band carries a number inside a small skein mark: 0 is lace, 7 is jumbo, and the steps between them are the whole scale. 4 (medium, sold as worsted in the US and aran in the UK) is the weight most patterns assume when they name none — it takes a 5–5.5mm hook and gives 11–14 single crochet over four inches. One step down, 3 (DK), takes 4–4.5mm; at the far end, 0 (lace), you are on steel at 1.5–2.25mm. The number is a bracket rather than a measurement, so two balls marked the same can still work up differently. The gauge line under it is the one to trust: match stitches over four inches and the yarns will substitute, whatever the numbers say.
| No. | Category | Hook | sc over 4 in. | Sold as (US) | Sold as (UK) | Used for |
|---|---|---|---|---|---|---|
| 0 | Lace | 1.5–2.25mm | 32–42 | Fingering / crochet thread | Cobweb / 2-ply | Thread motifs, edgings, doilies |
| 1 | Super fine | 2.25–3.5mm | 21–32 | Sock / fingering | 4-ply | Socks, fine shawls, small motifs |
| 2 | Fine | 3.5–4.5mm | 16–20 | Sport / baby | Sport | Baby layettes, light garments |
| 3 | Light | 4–5.5mm | 12–17 | DK / light worsted | DK | Small creatures, baby pieces, light garments |
| 4 | Medium | 5.5–6.5mm | 11–14 | Worsted / aran | Aran | Most creatures, blankets, hats, scarves |
| 5 | Bulky | 6.5–9mm | 8–11 | Chunky / craft / rug | Chunky | Baskets, fast throws, scarves |
| 6 | Super bulky | 9–15mm | 7–9 | Super bulky / roving | Super chunky | Bowls, cushions, heavy throws |
| 7 | Jumbo | 15mm+ | 6 or fewer | Jumbo / roving | — | Rugs, arm work, oversized accents |
Reading the ball band
The number sits inside a little skein outline, and it is the only part of the band that is standardised. Under it the spinner prints the hook they tested with and the gauge they reached — stitches and rows over four inches. Read the gauge first. Two balls can both be marked 4 and still want a different hook, because the mark is a bracket and the yarn sits somewhere inside it.
Grams tell you what the ball weighs, not how far it goes. Yardage tells you how far it goes. A 100g ball of medium yarn runs to roughly 200 yards; the same 100g in DK runs closer to 270, because the strand is thinner. When a pattern names a yardage rather than a number of balls, that is why — yardage survives a change of brand and a change of country, and a ball size does not.
Swapping one weight for another
The scale forgives one step and punishes two, and which way you are going decides what the hook has to do about it.
Down a bracket, or up one
One step is safe. Two is a different pattern. Going from medium down to DK, take the hook down with the yarn and work a swatch: the fabric comes out finer, the piece finishes about a tenth smaller, and a creature worked that way reads as a smaller creature rather than a wrong one. Going the other way, medium in place of DK, take the hook up and expect about a tenth larger.
Why skipping a step compounds
Skipping a step compounds. A blanket written for DK and worked in bulky is not a bigger blanket, it is a stiff one, because the stitch count that gave it drape now gives it board. Where a pattern can take a substitution it says so at the top, with the hook it wants for each weight it allows.
Fibre inside a weight
The number says how thick the strand is and nothing at all about what it is made of. Inside any one bracket you will find cotton, acrylic, wool and blends, and they behave differently under the same hook. Cotton has almost no give, so the stitch you make is the stitch you keep — useful when a round has to be counted back a month later. Acrylic has give, which forgives an uneven hand and hides a slightly loose round.
Wool blooms after a wash and closes small gaps; cotton does not, so a cotton piece has to be worked tight enough on the hook to begin with. That is the whole reason a creature pattern names a hook half a millimetre under the band's: the band is aiming for a comfortable fabric, and the pattern is aiming for one that will not show its stuffing.
Questions the ball band raises
If a pattern names no weight at all, what is it assuming?
Weight 4, the medium bracket, sold as worsted in the US and aran in the UK. It gives 11 to 14 single crochet over four inches on a 5mm or 5.5mm hook, and it is the bracket an unlabelled pattern is written against.
Which bracket should a stuffed creature be set in?
Medium (4) in cotton is the usual choice, worked on a 4 to 4.5mm hook rather than the 5.5mm the band suggests. The tighter fabric is the point: at band gauge the filling shows between stitches. DK (3) on a 3.5mm hook gives the same closed fabric at a smaller finished size.
Which hook goes with worsted?
5mm or 5.5mm — US H or I — for a fabric with some fall in it. Drop to 4 or 4.5mm for anything that will be stuffed.
Are DK and light worsted the same ball?
Both are weight 3 and they usually stand in for each other. Light worsted sits at the thick end of the bracket, so a swatch is worth the ten minutes whenever a finished measurement has to be right.
Does aran mean worsted, or something heavier?
In the US the two words name the same bracket, 4, and swap freely. In the UK, aran means the heavy end of it. So a UK aran and a US worsted will usually swap; a UK aran and a US light worsted usually will not without a hook change.
May a pattern be worked in a heavier yarn than it names?
One bracket up, with the hook up to match and a swatch worked first. Two brackets up changes the fabric rather than just the size, and no hook change will put the drape back.