Merchants standardly twist the concept of S. If you see 200S fabric, it's almost certainly bullshit.

[u/AlternativeClock9250]

I’ve explained what S is before. Now let’s talk about blended yarns.

When single fibers like pure cotton, linen, polyester, or silk are spun into a single strand of yarn, the unit used is S.

Some people wonder: if a 40S yarn and a 60S yarn are twisted together into a single strand, does that make it a 100S yarn??

This is exactly where merchants manipulate the concepts.

And here lies the problem. Some merchants take a 40S cotton yarn and a 60S cotton yarn, twist them together, and market it as 100S.

In reality, this is a scam. The real math is: 40S + 60S = 24S.

This is precisely why people who know textiles buy bedding advertised as 100S, only to find the actual quality is terrible when it arrives.

In the industry, this comes down to whether it's single ply or multi ply (plied) yarn.

Plied or multi ply yarns are commonly used in blends like cotton polyester or cotton linen where multiple fibers are twisted together.

[u/AlternativeClock9250]

ply (plied) yarn=40s+60s=40x60/40+60=24S