Yarn labels in North America usually carry a number from 0 to 7 in a skein symbol. The numbers come from the Craft Yarn Council's Standard Yarn Weight System, which groups yarns by thickness and gives the gauge and needle or hook sizes typical for each group.[1] The ranges are a starting point: the gauge your pattern asks for, checked with a swatch, is what counts.
Once you have a swatch, the Gauge Calculator turns it into stitches to cast on, and the Yarn Calculator into skeins.
Knitting
| Weight | Also called | Stitches per 4 in (10 cm) | Needles (mm) | Needles (US) |
|---|---|---|---|---|
| 0 Lace | fingering, crochet thread | 33 to 40 | 1.5 to 2.25 | 000 to 1 |
| 1 Super fine | sock, fingering, baby | 27 to 32 | 2.25 to 3.25 | 1 to 3 |
| 2 Fine | sport, baby | 23 to 26 | 3.25 to 3.75 | 3 to 5 |
| 3 Light | DK, light worsted | 21 to 24 | 3.75 to 4.5 | 5 to 7 |
| 4 Medium | worsted, afghan, aran | 16 to 20 | 4.5 to 5.5 | 7 to 9 |
| 5 Bulky | chunky, craft, rug | 12 to 15 | 5.5 to 8 | 9 to 11 |
| 6 Super bulky | roving | 7 to 11 | 8 to 12.75 | 11 to 17 |
| 7 Jumbo | roving | 6 or fewer | 12.75 and up | 17 and up |
Crochet
| Weight | Single crochet per 4 in (10 cm) | Hooks (mm) | Hooks (US) |
|---|---|---|---|
| 0 Lace | 32 to 42 (double crochet) | 1.4 to 2.25 | steel 6 to 8, regular B-1 |
| 1 Super fine | 21 to 32 | 2.25 to 3.5 | B-1 to E-4 |
| 2 Fine | 16 to 20 | 3.5 to 4.5 | E-4 to 7 |
| 3 Light | 12 to 17 | 4.5 to 5.5 | 7 to I-9 |
| 4 Medium | 11 to 14 | 5.5 to 6.5 | I-9 to K-10.5 |
| 5 Bulky | 8 to 11 | 6.5 to 9 | K-10.5 to M-13 |
| 6 Super bulky | 7 to 9 | 9 to 15 | M-13 to Q |
| 7 Jumbo | 6 or fewer | 15 and up | Q and up |
Steel hooks, used for thread, are numbered the opposite way from regular hooks: the higher the number, the smaller the hook.
Reading the ranges
- Stitches per inch or per centimeter: divide the 4-inch count by 4, or the 10 cm count by 10. Worsted at 16 to 20 stitches per 4 inches (10 cm) is 4 to 5 stitches per inch, or 1.6 to 2 per centimeter.
- Thicker yarn, fewer stitches: each step up in weight roughly means fewer, larger stitches, a bigger needle or hook, and fewer yards per gram.
- Substituting yarn: pick one in the same weight category and check the yards per skein and the fiber, then swatch. Two yarns labeled the same weight can still knit to different gauges.
Sources and notes
The numbers in brackets point to these sources.
- Craft Yarn Council, Standard Yarn Weight System. Accessed 17 October 2026.Yarn weight categories 0 to 7 with typical knit and crochet gauges over 4 inches and recommended needle and hook sizes. The council describes them as guidelines only. Back to text