That Yarn · Journal

Understanding Yarn Weight and Nm: A Guide for Makers

How industrial cone yarn is measured — and how to convert it for knitting, weaving, and spinning.

Whether you knit by hand, work a machine, or weave, reading Nm counts is the key to choosing cone yarn with confidence. Industrial cone yarn is labelled differently from retail skeins. Once the system clicks, it opens a world of fine, mill-quality fiber that rarely reaches the retail shelf.

This guide covers what Nm means, how to convert it to yards and US weight categories, why mohair and wool follow different labelling customs, and how to ply single strands to reach the weight you want.

What is Nm?

Nm — Number metric — is the textile industry's standard measure of yarn fineness. It tells you how many meters of a single strand weigh one gram.

Length in meters = Nm × weight in grams

A 1/28Nm yarn holds 28 meters in every gram — so a 100g cone carries 2,800 meters. The rule to remember: the higher the Nm, the finer the yarn. A 1/60Nm single is gossamer-fine; a 1/8Nm single is thick and substantial.

Reading plied yarns

Most cone yarn is not a single strand. It is spun fine, then plied — twisted together — to reach its final weight. This is written as ply over count.

A label like 2/28Nm means two strands of 28-count twisted together. Each strand is 28 meters per gram on its own. Combined into two, the finished yarn measures 14 meters per gram — the same fiber, now twice as substantial.

The ply count, not the single, is what your hands feel.

Two ways of writing the same measure

Across cone yarn you will meet two conventions. They describe the same Nm system — different fibers simply follow different trade customs.

Wool, cashmere, and most animal fibers

Written as ply over count: 2/30Nm, 2/48Nm. Two strands of a given count, twisted together.

Mohair and fine brushed yarns

Written as 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 too, a higher number means a finer single — and usually a more luxurious clip. 9,500 is an entry point. 13,000 and finer are the softest kid-mohair grades.

Converting Nm to US weight categories

US makers think in weight categories — fingering, DK, worsted. Cone yarn rarely arrives in one of these tidy boxes, because it is spun as a single to be plied. But once you know the finished meters per 100g, it maps cleanly.

To convert meters to yards: yards = meters × 1.09361

Reaching your weight by plying

As a hand knitter, you are not bound by the yarn's single-strand thickness. Hold several strands together — ply them — to reach the weight you want. A worked example:

Notice the direction: more strands means fewer meters per gram, which means a heavier, more substantial yarn. Five strands of 2/30Nm combine to roughly 1/3Nm — about 300 meters per 100g, a fingering-to-sport weight that works beautifully for socks.

This table is a starting point. Fiber content and your own tension both shift the result — always swatch and wash before committing to a project.

Nm compared to other systems

You may see other measures on imported or industrial yarn:

Tex

Grams per 1,000 meters. Higher Tex means thicker yarn — the reverse of Nm.

Denier

Grams per 9,000 meters, used mostly for filament and silk.

WPI — wraps per inch

A hands-on method: wrap the yarn around a ruler and count the wraps in one inch. More wraps means finer yarn.

Nm remains the most precise for cone yarn, because it reflects the spun structure directly rather than an approximation.

Frequently asked questions