Yarn Weight Converter
Convert between yarn weight systems.
Compare US, UK, and Australian yarn weights with needle sizes and gauge recommendations.
Yarn weight categories are standardized by the Craft Yarn Council (CYC) to help knitters and crocheters substitute yarns and interpret patterns from different countries. Weight refers to thickness, not mass.
CYC Standard Weight System (0–7 scale):
| CYC # | Name | Wraps per inch | Knit gauge (4") | Common uses |
|---|---|---|---|---|
| 0 | Lace | 18+ wpi | 32–42 sts | Shawls, doilies |
| 1 | Super Fine | 14–18 wpi | 27–32 sts | Socks, baby items |
| 2 | Fine | 12–14 wpi | 23–26 sts | Light garments |
| 3 | Light | 11–12 wpi | 21–24 sts | DK weight projects |
| 4 | Medium | 9–11 wpi | 16–20 sts | Sweaters, hats |
| 5 | Bulky | 6–8 wpi | 12–15 sts | Blankets, scarves |
| 6 | Super Bulky | 5–6 wpi | 7–11 sts | Quick blankets |
| 7 | Jumbo | 1–4 wpi | 6 or fewer | Arm knitting |
Wraps Per Inch (WPI), the universal thickness test:
Wrap yarn around a ruler for 1 inch without stretching it, count the wraps → WPI
Note that WPI counts run in the opposite direction to the CYC numbers: thin yarn gives a high count because more strands fit in the inch. Sources disagree by a wrap or two at the boundaries, since it depends how tightly you wind, so treat a borderline reading as a boundary rather than a verdict.
Cross-system equivalents:
| CYC Name | UK Name | Australia |
|---|---|---|
| Super Fine (1) | 2-ply / 3-ply | 3-ply |
| Light (3) | DK | 8-ply |
| Medium (4) | Aran | 10-ply |
| Bulky (5) | Chunky | 12-ply |
Needle/hook size conversion:
- CYC 4 (Medium/Worsted): US 7–9 needles (4.5–5.5mm)
- CYC 5 (Bulky): US 9–11 needles (5.5–8mm)
- CYC 6 (Super Bulky): US 11–17 needles (8–12mm)
Gauge swatch rule: Always knit a 4"×4" swatch before starting any project. Gauge trumps the suggested needle size — adjust until your stitch count matches the pattern.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.