What Does 100s Cotton Mean?

The short answer: "100s" is a yarn count. It tells you how fine the cotton yarn is, not how many threads are in the fabric. One pound of 100s yarn stretches 84,000 yards (about 169 km per kilo). The higher the number, the finer the yarn, and the smoother, lighter and softer the finished cloth tends to feel.

Bedding labels love a number. Thread count, momme, GSM, and then there is "100s", which sits on a label looking important while explaining absolutely nothing.

It is one of the most useful numbers in cotton, and one of the least understood. Once you know what it measures, you will never read a sheet label the same way again.

What Does the "s" in 100s Cotton Stand For?

The "s" simply stands for the cotton count: the way spinners have measured how fine a yarn is since the days of the Lancashire cotton mills. It is still the standard used around the world today.

The idea is charmingly old fashioned:

Take one pound of cotton. Spin it into lengths of 840 yards. Count how many lengths you get. That number is the count.

So a 100s yarn means one pound of cotton has become 100 of those lengths, 84,000 yards in all. A 40s yarn makes only 40 from that same pound, so each strand is thicker.

To put it in more tangible terms: a single gram of 100s yarn runs for roughly 169 metres, about one and a half football pitches laid end to end.

The key thing to remember is that the scale is indirect. A bigger number means a finer yarn.

Why Does Finer Yarn Feel Softer?

This is where the science gets genuinely interesting, because softness is not really about the cotton plant. It is about the surface of the yarn.

Fewer loose ends. Every cotton yarn is made by twisting thousands of individual fibres together. Each fibre has two ends, and some of those ends inevitably poke out of the yarn's surface. Textile scientists call this hairiness. Hairier yarns feel slightly rougher against the skin and catch light unevenly, which gives a duller look.

Long fibres make fine yarn possible. You cannot spin a yarn as fine as 100s from short, stubby fibres; they simply will not hold together. Fine counts need long staple cotton, where individual fibres are typically around 30 mm or longer, and the finest yarns often use extra long staple varieties of 35 mm and above. Longer fibres mean fewer ends per metre of yarn, and fewer ends mean a smoother surface.

Combing removes the rest. Before spinning, high quality cotton is combed, a process that removes the short fibres and aligns the long ones in parallel. The result is a cleaner, more lustrous yarn with noticeably less fuzz.

Less fuzz, less pilling. Those protruding fibre ends are also what eventually tangle into little balls on the surface of fabric. Research has linked lower yarn hairiness directly to reduced pilling¹, which is why fine, combed, long staple yarns tend to stay smooth for longer.

Lighter cloth, better drape. Finer yarns produce a lighter fabric that drapes and moves with you, rather than sitting stiffly on top of you. That suppleness is much of what people mean when they describe cotton as "silky".

Is a Higher Yarn Count Always Better?

Not automatically, and it is worth being honest about this.

A very fine yarn is, by definition, thinner, and a thin yarn made from poor fibre will be weak. A high count number on its own tells you how fine the yarn is, not how good the cotton was. What makes a 100s yarn worth having is the combination behind it: long staple fibre, careful combing and a well made weave.

That is also why yarn count matters more than thread count. Thread count measures how many threads sit in a square inch of fabric, and it can be inflated by twisting several thin, low grade strands together and counting each one. Yarn count describes the quality of the thread itself. (We go deeper into this in an upcoming piece on why thread count is a myth.)

How Does 100s Cotton Compare to Other Counts?

Ranges are indicative. Feel also depends on fibre quality, weave and finishing.

Cotton and Sleep: Why the Yarn Matters at Night

Cotton fibres naturally draw in water vapour. Even in an ordinary bedroom, cotton holds around 8% of its own weight in moisture² while still feeling completely dry. As your skin releases moisture through the night, a cotton sheet takes some of it in and lets it escape back into the room, so you stay dry rather than clammy. Polyester, by comparison, absorbs less than 1%.

A fine, lightweight cotton lets that moisture and heat move more freely than a dense, heavy cloth. It is a small thing, but sleep is made of small things. Your body naturally cools as you drift off, and anything that helps it do so quietly, without you waking to kick off a layer, is working in your favour.

Where We Use 100s Cotton

Our Signature Cotton Bedsheet Sets are woven from 100s cotton, and this is where a fine yarn truly earns its place.

Your sheets are the fabric you lie on, night after night. Every quality covered above, the smooth surface, the light drape, the quiet way it handles moisture, is something you feel directly against your skin. A finer yarn simply makes for a calmer place to rest.

The sets come in a range of colourways, each chosen to sit softly in a restful bedroom rather than compete with it.

Our cotton is certified to OEKO-TEX® Standard 100, meaning it has been tested for harmful substances, and it is made by family owned partners we work with directly, without intermediaries. Designed in Zurich, delivered free across Switzerland.

Discover our Signature Cotton Bedsheet Sets.

Frequently Asked Questions

What does 100s mean on bedding?

It means one pound of cotton has been spun into 100 lengths of 840 yards each. It describes how fine the yarn is, not how many threads are in the fabric.

Is 100s cotton better than 60s cotton?

100s is finer and generally softer and lighter than 60s. Whether it is "better" depends on the fibre quality behind it; look for combed, long staple cotton as well as a high count.

Is yarn count the same as thread count?

No. Yarn count measures the fineness of a single yarn. Thread count measures how many threads are woven into one square inch of fabric. A high thread count can be achieved with thick, low quality yarn, so yarn count is the more reliable guide to feel.

Does 100s cotton pill?

Fine, combed, long staple yarns have fewer loose fibre ends on their surface, so they are less prone to pilling than coarser yarns made from shorter fibres. Gentle washing and avoiding high heat in the dryer help it stay smooth for longer.

Curious how cotton stacks up against other fills? Read Silk vs Cotton vs Down: Which Duvet Is Best for You?, discover What is a silk duvet? or explore more in the Elaine & Cocoon Journal.

¹ Wang, X. et al. (2007), "A controlled experiment on yarn hairiness and fabric pilling", Textile Research Journal.

² Typical moisture regain of cotton at 20°C and 65% relative humidity, compared with under 1% for polyester. See Morton, W.E. & Hearle, J.W.S., Physical Properties of Textile Fibres.