What does a yarn count (Nm) mean and how is its thickness determined?

When talking about yarn, one of the most common questions is:
"How thick is this yarn?"

In the textile world, however, thickness is not indicated like it is for an electrical wire or a rope.
Instead, a system called yarn count is used, and one of the most common in Europe is Nm.

Let's look together at what it is, how it works, and why a higher number indicates a thinner yarn (yes, it's the opposite of what many people think!).

What is yarn count

The count is a numerical value that serves to indirectly measure the thickness of the yarn, relating length and weight.

In simple words:

• we don't measure "how wide" the yarn is

• but how much length of yarn is contained in a certain weight

This method is much more precise and reliable, especially for fine yarns like wool, cashmere, silk, or cotton.

What Nm means

Nm stands for Metric Number.

👉 It indicates how many meters of yarn there are in 1 gram of weight.

• Nm 1 → 1 meter weighs 1 gram

• Nm 2 → 2 meters weigh 1 gram

• Nm 10 → 10 meters weigh 1 gram

• Nm 28 → 28 meters weigh 1 gram

🔑 The higher the Nm number, the finer the yarn.
🔑 The lower the Nm number, the thicker the yarn.

Why don't we measure thickness "with a ruler"?

Because:

• yarns are never perfectly cylindrical

• softness, twist, and fiber change visual perception

• two yarns can look similar but have completely different yields

The Nm count, however, allows us to:

• objectively compare different yarns

• predict fabric yield, consumption, and fineness

• choose the right machine or needles to work with it

What Nm 2/28, Nm 2/15, etc. mean

Here's where another important detail comes in.

Nm 2/28 means:

• 28 Nm = count of the single ply (very fine)

• 2 ply = two plies twisted together

👉 The final result will be thicker than a single 28, but more regular and resistant.

Some common examples

• Nm 2/28 → very fine yarn (knitwear gauge 12–14)

• Nm 2/15 → medium (gauge 7–8)

• Nm 2/7 → thick (gauge 5–6)

Imagine roads:

• a country lane → thick yarn (low Nm)

• a main road → medium yarn

• a super-thin single-lane highway → very fine yarn (high Nm)

Now imagine weighing 1 gram of road:

• on the country lane, you don't go very far

• on the super-thin highway, you go many kilometers

👉 This is exactly the concept of Nm.

Why yarn count is fundamental for knitters or machine knitters

Knowing the count is useful for:

• choosing needles, hooks, or machine gauge

• calculating actual consumption

• avoiding production errors

• understanding if a yarn is suitable for:

  • scarves

  • fine knitwear

  • heavy winter garments

  • light or compact fabrics

The Nm is not a mysterious code, but an intelligent and precise way to express how fine a yarn is.

👉 High number = fine yarn
👉 Low number = thick yarn

Once this principle is understood, reading yarn technical sheets becomes simple and logical, even for those not in the trade.