Knitting reference
Yarn weight chart — UK, US, WPI & held double
DK, 4 ply, fingering, worsted, aran… yarn naming gets confusing very quickly once a pattern or ball band crosses an ocean. Use this as a practical comparison, not a substitute for swatching.
| Common UK name | CYC / common US category | Approx. WPI | Typical needles | Typical stocking-stitch gauge / 10cm |
|---|---|---|---|---|
| Lace / very fine | 0 Lace | 30–40+ | 1.5–2.25 mm | 33–40+ sts |
| 4 ply / fingering / sock | 1 Super Fine | 14–30 | 2.25–3.25 mm | 27–32 sts |
| Sport / baby | 2 Fine | 12–18 | 3.25–3.75 mm | 23–26 sts |
| DK | 3 Light | 11–15 | 3.75–4.5 mm | 21–24 sts |
| Aran / worsted | 4 Medium | 9–12 | 4.5–5.5 mm | 16–20 sts |
| Chunky | 5 Bulky | 6–9 | 5.5–8 mm | 12–15 sts |
| Super chunky | 6 Super Bulky | 5–6 | 8–12.75 mm | 7–11 sts |
| Jumbo | 7 Jumbo | 1–4 | 12.75 mm+ | 6 sts or fewer |
What does WPI mean?
WPI means wraps per inch. Wrap the yarn neatly around a ruler or another object of consistent thickness, with each strand touching but not overlapping, and count the wraps across one inch.
It is useful for mystery yarn and for comparing two possible substitutes, but it is still subjective: pulling the yarn tighter changes the result. Measure more than once and swatch before committing to a garment.
What happens when you hold yarn double?
Holding two strands together makes a thicker working yarn, but there is no perfectly reliable equation because two yarns with the same label can still differ in actual thickness, fibre, twist and loft.
| Held together | Useful starting assumption |
|---|---|
| 2 strands of lace | about 4 ply / fingering |
| 2 strands of 4 ply / fingering | about DK |
| 2 strands of DK | about aran / worsted |
| 2 strands of aran / worsted | about chunky |
Treat those as starting points only. Two strands of a plump DK may behave much thicker than two strands of a fine DK. Knit the swatch with both strands held exactly as you intend to use them and judge the resulting gauge and fabric.
Is 4 ply the same as fingering? Is aran the same as worsted?
In modern knitting shops, UK 4 ply and US fingering often occupy roughly the same part of the weight spectrum, while aran and worsted overlap heavily. They are useful translations, not guarantees that any two yarns will substitute perfectly.
Ply count can also describe how a yarn is constructed rather than its finished thickness, so a modern yarn labelled with a number of plies should not automatically be assigned a weight from that number alone.
What needle size should I use for DK, aran or chunky yarn?
The ranges in the chart show common starting points. Your pattern may deliberately use a smaller needle for a firm fabric or a larger one for drape or lace. Start with the pattern, then change needle size if your blocked swatch does not match the stated gauge.
Weight, gauge, needle-range and WPI guidance checked against the Craft Yarn Council standard yarn-weight and WPI systems. These are industry guidelines and ranges overlap.