That Yarn

Understanding Yarn Weight (Nm)

What is Nm?

Our cone yarns are measured in Nm — Number metric, the textile industry's standard for yarn fineness.

Nm tells you how many meters of a single strand weigh one gram. The higher the Nm, the finer the yarn.

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Reading the numbers

A single number is the fineness of one strand.

• 30Nm means 30 meters per gram. A fine strand.

• 10Nm means 10 meters per gram. A thicker strand.

A number like 2/30Nm describes a plied yarn — two strands of 30Nm twisted together. Each strand is 30 meters per gram on its own. Twisted into two, the finished yarn measures 15 meters per gram — the same fiber, now twice as substantial.

Most cone yarn is spun as a fine single, then plied to reach its final weight. The ply count, not the single, is what your hands feel.

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Two ways of writing the same measure

Across our cones you will see two conventions. They describe the same Nm system — different fibers simply follow different trade customs.

Wool, cashmere, and most animal fibers are written as ply over count. 2/30Nm means two strands of 30-count twisted together.

Mohair and fine brushed yarns follow a different custom — a single large number. A 1/13Nm mohair is often written as 13,000Nm; a 1/9.5Nm as 9,500Nm. The count simply carries three more digits. Japanese mills tend to write 1/13Nm; Italian mills more often write 9,500Nm for the same class of yarn.

Here, a higher number means a finer single — and usually a more luxurious clip. 9,500 is an entry point. 13,000 and above are finer still.

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Why Nm matters

Finer, higher-Nm yarns ask more of the mill. They require longer-staple fiber, more precise spinning, and greater consistency across the cone. This is the same fineness prized for stitch definition, breathability, and drape in the yarns these mills supply to fashion houses.

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Machine-grade yarn, hand-knitting ready

These yarns were spun for machine knitting and weaving. As a hand knitter or crocheter, you will usually hold several strands together — plying — to reach fingering, DK, or worsted weight.

Every cone at That Yarn lists its single-strand Nm and a recommended ply on its product page. A plying-guide card is tucked into your first order.

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Cone Yarn Ply Reference Table

For wool, cashmere, and other animal fibers.

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A few things to know

Nm can vary slightly with fiber content — wool, cashmere, and silk behave differently. Your own tension changes the finished feel. Always swatch before a project, to test gauge, density, and shrinkage after washing.

This table is a starting point. Mixing fibers, colors, and strand counts is where the interesting textures begin.

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Some yarns don't come back.

Have a question about a specific cone? Write to us at hello@thatyarn.com — we answer every email.