What is the difference between DK and worsted weight yarn?

DK (Double Knitting) is the UK term for a medium-light weight yarn, typically knit on 3.75-4.5mm needles at 21-24 stitches per 10cm. Worsted is a US term for a slightly heavier yarn, knit on 4.5-5.5mm needles at 16-20 stitches per 10cm. Worsted is closer to UK aran weight. The terms are often confused because "worsted" can also refer to a spinning method.

What does "ply" mean in yarn weight?

Ply originally referred to the number of strands twisted together to make the yarn. However, modern ply counts are standardised labels rather than literal strand counts: 4-ply means fingering weight, 8-ply means DK, 10-ply means aran/worsted, and 12-ply means chunky. A yarn labelled 4-ply could actually have 2, 3, or 6 physical plies.

What is WPI and how do I measure it?

WPI stands for Wraps Per Inch. To measure it, wrap yarn around a ruler or pencil snugly (not stretched, not loose) and count how many wraps fit in one inch (2.54cm). This gives you an objective measurement of yarn thickness regardless of what the label says. WPI is especially useful when the ball band is missing or when assessing handspun yarn.

KnitCalcs

Yarn Weight Converter — UK, US & Australian Systems

Convert between yarn weight naming systems. See equivalent names, needle sizes, gauge ranges, and meterage for any yarn weight.

Select Yarn Weight

Choose a yarn weight to see all equivalent names

How We Calculate This

This converter provides the equivalent names across yarn weight systems used in the UK, US, Australia, and by the Craft Yarn Council. It also shows the recommended needle sizes, typical gauge range, and expected meterage per 100g.

How it works

Yarn weight categories are standardised groupings based on the thickness of the yarn strand. While exact boundaries vary slightly between systems, the categories map to specific gauge ranges and needle sizes that are consistent worldwide.

UK system: Uses names (4-ply, DK, Aran, Chunky) and ply numbers
US system: Uses names (Fingering, Sport, Worsted, Bulky)
Australian system: Primarily uses ply numbers (4 ply, 8 ply, etc.)
Craft Yarn Council: Uses numbered categories (0-7)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard yarn weights and gauge. Results may vary with individual tension, yarn brand, and needle size.