Yarn Count

Yarn countDerived from the Sino-Korean combination of 'beon' (番, meaning order or number) and 'su' (手, meaning count or unit), which originated from numbering threads by measuring their weight and length.

A unit indicating yarn thickness, where a higher number denotes a finer yarn

A unit that represents thickness by the length of yarn per fixed weight. The smaller the number, the thicker the yarn, making knitted or woven fabrics thicker and stiffer; the larger the number, the finer the yarn, resulting in thinner and lighter fabric. In clothing product descriptions, it is commonly abbreviated as 'su' (count), such as '10s' or '16s'.

Difference in yarn thickness and fabric thickness — Explanatory image created by hmmm

Appearance

When the number is smaller, such as 10s or 14s, thicker yarn is used, showing a distinct surface texture and substantial thickness. Conversely, as the number gets larger, such as 30s or 40s, the yarn becomes finer, resulting in a dense, smooth surface weave and a thin, light appearance.

When choosing

When you want clothing that has little see-through and holds a stiff shape, check for 10s–16s fabric. When choosing thin, light clothes or t-shirts to wear as innerwear, checking for 30s or 40s indications serves as a standard.

Additional information

Denier: A unit of synthetic fiber thickness; unlike yarn count, the larger the number, the thicker the yarn.
Gauge: Means the number of needles per 1 inch, indicating the knit density rather than the yarn thickness.

Some images are explanatory images created with AI.