Thread Count FAQ: All You Need to Know

By Mario Esposito
Last Updated: March 22, 2019

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What do you take into consideration when choosing cotton bed linens? Most people looking for dependable sheet sets go by the thread count. It’s often highlighted on product labels; with higher numbers marketed as a marker of superior quality, durability and softness.

But is thread count really important? What’s the math and science behind thread counts, and why do people assume that higher means better? Marketing can be misleading, but facts are facts! We tell it like it is in this article, and give you the low down on thread count.

Bed sheets detail

What Is Thread Count?

Thread count is a baseline number that is determined by the number of threads that are present in a square inch of fabric.

Fabrics may be made using different types of weaves, but they all have threads that are horizontal and vertical—weft and warp, respectively, in industry terms. A single weft thread is called a pick, and a single warp thread is called an end.

Threads of both orientations are included in the thread count. For example: 150 weft threads and 150 warp threads result in a 300 thread count.

Thread count is also known as TPI (Threads Per Inch).

How Is Thread Count Calculated?

Technically, it is as easy as counting threads. However, some manufacturers regard each fiber or ply as one thread, to justify a higher thread count. 

Sometimes, extra horizontal threads can also be woven into the fabric. The latter results in an unequal ratio of weft and warp threads, but a higher thread count overall. In industry terms, this means that the fabric has a EPI (Ends Per Inch) that is higher than its PPI (Picks Per Inch).

Fiber, Thread, Ply: What’s the Difference?

A fiber is simply something that is long and thin. Cotton fibers are formed by natural growth, in bolls that form around the seeds of the plant. Without human intervention, cotton bolls aid in spreading and dispersing seeds.

A thread is actually a type of yarn, which in turn is a term for a long length of many fibers spun together. The most common example is cotton thread, which is made of cotton fibers, and is used to make cloth.

A ply is a little bit more complicated to explain. Plying is a process that’s a little like a repetition of what fibers go through to turn into yarns or threads. Two or more strands of yarn or thread are twisted together, ostensibly to produce a stronger and more balanced end product. The balance comes from the direction of the twist. It’s the opposite of the direction the fibers were spun together, so it evens out the tension and reduces the tendency of the resulting thread to twist on itself.

How Does Plying Affect Thread Count?

The plying process is widespread. In fact, most commercially available yarns and threads are two-ply or more. Therein lies the difficulty. Consumers think that all thread counts are counted the same way, using the same thread definition, but that’s not true at all.

Some sheet set manufacturers will count the threads as is, which is what the average person would expect. This way of calculating thread count has a definite ceiling, as the most number of threads that can be woven into a square inch is about 500.

Other sheet set manufacturers will count the threads by ply, which is still technically correct. After all, each ply is a strand of thread or yarn. This is how you get very high thread counts! A 1000 thread count is impossible if you count threads as is, but understandable if the threads used are two-ply and the plies are counted instead.

Does a Higher Thread Count Always Mean Better Quality?

A higher thread count is better, but only if what’s counted are actual threads (ends and picks) and not plies. In general, if the thread count is above 500, be wary.

Thread count is important, but you have to know how to decipher the thread count shown by the manufacturer. As we mentioned above, not all thread counts are determined the same way.

When Is a Thread Count Too Low?

Never get sheets with a thread count under 180. For a more practical way to assess sheets, hold them up against a light. If the light shines through tiny holes in between the weave, the thread count is too low. The fabric won’t last long with regular use and washing, and won’t be soft or comfortable.

That being said, higher is not always better. A 300 thread count sheet set from a reputable manufacturer is almost always going to be of higher quality than a 1000 thread count sheet set on sale.

What’s Wrong with 1000 Thread Count Sheets?

What’s wrong with a thread count above 500? Let’s break this down: We’ve mentioned above that the highest thread count possible without counting plies is more or less 500. It can be assumed, then, that anything above that is calculated by ply.

There is nothing wrong with using multi-ply threads, but the whole plying process exists to create a sturdier, more long-lasting end product. What’s being unsaid here is that each ply by itself is not at par with a thread used for weaving. Often, plies are strands of thread made from shorter cotton fibers.

A ply is not equal to a thread in terms of quality, and is in fact much weaker. Multi-ply threads are more often than not cheaper and heavier. A high thread count and impressive price tag may lead you to believe that you are buying luxury, when in fact the fabric may be scratchier. This is due to short fibers poking out of the fabric weave.

What Is the Best Thread Count for Your Sheets?

Ideal sheet sets generally have a thread count of about 200 to 400. Too low and durability will suffer; too high and lack of breathability will be a problem.

Thread count is a good indicator the density and heaviness of a fabric. While high density means a longer usable lifespan and a smoother feel, it also means a tighter weave and less permeability. The latter won’t be a problem for cold climates, but if you sleep hot or live somewhere with scorching summers, it may not be the best for you.

Another reason we don’t recommend an actual thread count above 400 is the cost. The only way to fit the maximum amount of threads into a square inch is to use only the finest materials. These are more expensive to produce, resulting in heftier price tags.

More than just thread count, check for the quality of the cotton, too! Organic cotton in general is good, and Egyptian cotton is well-known to be the best. Supima cotton is another great option, as it is US-grown and as soft and high quality as Egyptian cotton.