Yarn weight has nothing to do with how heavy the ball is. It means how thick the strand is — and it is the single most important thing to get right, because it decides your hook size, your gauge, and whether the finished thing is the size you intended.
Here is the whole system on one page, written for crocheters rather than knitters.
The yarn weight chart
The Craft Yarn Council numbers yarn from 0 to 7. That number is printed on almost every ball band, usually inside a little skein symbol.
| # | Also called | Crochet hook | Gauge (sc per 4″) | Best for |
|---|---|---|---|---|
| 0 | Lace, thread, cobweb, 2-ply | 1.5–2.25 mm (steel 6–8) | 32–42 | Doilies, thread crochet, fine shawls |
| 1 | Super fine, fingering, sock, baby | 2.25–3.5 mm (B/1–E/4) | 21–32 | Socks, lightweight shawls, baby garments |
| 2 | Fine, sport, baby | 3.5–4.5 mm (E/4–7) | 16–20 | Baby blankets, light cardigans, amigurumi detail |
| 3 | Light, DK, light worsted | 4.5–5.5 mm (7–I/9) | 12–17 | Garments with drape, hats, lighter blankets |
| 4 | Medium, worsted, aran, afghan | 5.5–6.5 mm (I/9–K/10½) | 11–14 | Almost everything. Blankets, hats, amigurumi, sweaters |
| 5 | Bulky, chunky, craft, rug | 6.5–9 mm (K/10½–M/13) | 8–11 | Fast blankets, winter hats, scarves, baskets |
| 6 | Super bulky, roving | 9–15 mm (M/13–Q) | 6–9 | Weekend blankets, chunky scarves, floor cushions |
| 7 | Jumbo, extreme | 15 mm and up (Q and up) | 5 and fewer | Arm crochet, rugs, oversized throws |
Two things worth knowing about that table. The hook sizes are a starting point, not a rule — a pattern will tell you what it wants, and your own tension may need you to go up or down a size. And the gauge column is single crochet, which runs tighter than double crochet; if your pattern uses dc, expect fewer stitches per four inches.
The crochet journal I call my magic tool
My best seller: a vintage-look printable journal that’s inspiring, a little funny, and nothing like a plain planner. Inside: hook conversion chart, stitch symbol guide, yarn stash inventory, row counter, pattern notes, and more.
Love blanket stitches too? 50+ easy-yet-unique blanket stitches – $27
What each weight is actually like to work with
0 – Lace. Closer to sewing thread than yarn. Almost always worked with a steel hook for doilies and fine edgings. Slow, and unforgiving of mistakes, but nothing else produces that delicacy.
1 – Super fine. Sock yarn. Hard-wearing, usually with a little nylon in it. Beautiful for shawls, very slow for anything large. Not a good first yarn.
2 – Fine. Sport weight. The traditional choice for heirloom baby blankets — light enough to be safe over a baby, fine enough to look delicate.
3 – Light / DK. The quiet favourite for garments. Thick enough to work up at a reasonable speed, fine enough that a cardigan drapes instead of standing up on its own.
4 – Medium / worsted. If a free pattern does not specify, assume it means this. It is the most widely available weight, the cheapest per yard, and the easiest to find in a huge colour range. Start here.
5 – Bulky. Where projects start finishing fast. A bulky blanket takes a fraction of the time of a worsted one, and the stitch texture reads clearly from across a room.
6 – Super bulky. The chenille-style blanket yarns live here. Wonderfully quick and very cosy, though the fabric can be dense and it hides fine stitch detail — keep the pattern simple.
7 – Jumbo. Enormous. Often worked with the arms rather than a hook. Fun, fast, and expensive by the metre.
How to tell what weight a yarn is
Check the ball band first. Nearly every label carries the standard skein symbol with a number from 0 to 7 inside it. Our guide to reading a yarn label covers every other number on there too.
No label? Wrap the yarn around a ruler for one inch, laying the strands side by side without squashing them, and count the wraps:
| Wraps per inch | Weight |
|---|---|
| 30+ | 0 – Lace |
| 14–18 | 1 – Super fine |
| 12–14 | 2 – Fine |
| 11–12 | 3 – Light / DK |
| 9–11 | 4 – Medium |
| 6–9 | 5 – Bulky |
| 5–6 | 6 – Super bulky |
| Under 5 | 7 – Jumbo |
Substituting one yarn for another
You can nearly always swap a yarn for another of the same weight number. What changes is everything else, and that is where projects go wrong.
- Match the yardage, not the ball weight. Two 100 g balls of the same weight can differ by 80 metres. Add up the metres the pattern calls for and buy at least that.
- Fibre changes the drape. Acrylic holds its shape, cotton is heavier and stretches downward, wool has bounce. A cardigan in cotton will hang longer than the same one in acrylic.
- Always swatch for anything that has to fit. For a blanket you can usually get away without. For a garment you cannot.
- Buy one dye lot. The number is printed next to the colour name. Two lots of the same colour can be visibly different in daylight.
Which weight should I use?
| If you want to make… | Use |
|---|---|
| A baby blanket that looks heirloom | 2 or 3 |
| A baby blanket this weekend | 5 or 6 |
| Amigurumi with tight, gap-free stitches | 3 or 4, with a smaller hook than usual |
| A cardigan or sweater that drapes | 3 or 4 |
| Dishcloths and washcloths | 4, in cotton |
| A winter hat or scarf | 4 or 5 |
| A rug or basket that holds its shape | 6 or 7 |
| Doilies and fine edgings | 0 |
Questions we get asked
What weight is Red Heart Super Saver?
Weight 4, medium. It is the default worsted acrylic in a great many free patterns.
What weight is Bernat Blanket yarn?
Weight 6, super bulky. It is the chenille-style yarn behind most of the very fast blanket patterns.
Is aran the same as worsted?
Close enough for most projects — both sit at weight 4. Aran is a UK term and tends to run slightly thicker. Swatch if the fit matters.
Is DK the same as light worsted?
Yes. Both are weight 3, and patterns use the names interchangeably.
Can I use a different hook than the label suggests?
Absolutely, and crocheters often do. A larger hook gives a looser, drapier fabric; a smaller one gives a denser fabric that holds its shape — which is why amigurumi is worked tightly. The label is a suggestion, not an instruction.
Why does my project keep coming out the wrong size?
Nearly always gauge rather than yarn weight. Your tension differs from the designer’s, so the same yarn and hook give you a different size. Make a swatch and change hook size until your stitch count matches the pattern.
What is the most common yarn weight?
Weight 4, medium worsted, by a wide margin. If you are buying your first yarn, buy that with a 5.0 mm (H/8) hook.
Keep these nearby
- Hook Size & US/UK Conversion Chart — downloadable, and essential if you follow patterns from both countries.
- How to Read a Yarn Label — every other number on that paper band.
- How Much Yarn Do I Need? — so you buy the right amount in one dye lot.
- Crochet Abbreviations — for when the pattern stops making sense.
- Crochet Stitch Library — a tutorial for every stitch named on this page.
Where these standards come from
The yarn weight numbering on this page is the Standard Yarn Weight System published by the Craft Yarn Council, the industry body that sets these categories for yarn manufacturers. The wraps-per-inch method is described in their guide to measuring wraps per inch. The numbers are an open industry standard; the tables, explanations and hook suggestions here are written by us, for crocheters rather than knitters.
