Here's why thread count doesn't really matter when buying sheets — and what you should look for instead

• Thread count is the number of yarns in a square inch of fabric.
• To a point, higher thread counts may mean higher-quality sheets, but it's not a guarantee.

Thread count is the number of yarns in a square inch of sheeting. It's long been considered an easy way to shop for luxurious sheets: The higher the thread count, the better the bedding.

But that's not necessarily the case because of the way some brands count yarns. Plus, not all types of sheets use thread count as a designator of quality. Manufacturers of cotton sheets list the thread count, but you won't always find a number on your best linen sheets, for example. Here's what you need to know about sheet thread counts.

What is thread count?

Woven fabric is made of horizontal (weft) and vertical (warp) yarns. If a piece of fabric has 100 warp yarns and 100 weft yarns in a square inch, it would be a 200-thread-count sheet.

The reason people often associate higher thread counts with luxury is the quality of the yarn. Finer threads feel silkier, and you can weave more into a square inch than a thicker yarn.

The woven pattern also factors into the thread count. For percale sheets, the pattern alternates with a thread going over then under, over then under. In a sateen weave, threads skip over three or four yarns, then go under one. The result is a denser, smoother fabric than a light and crisp percale.

Sateen sheets often have a higher thread count because it's easier to fit more yarns into the looser grid pattern. For a deeper dive on this, check out our guide on percale vs. sateen cotton.

Are higher thread-count sheets better?

Not necessarily. "You see sometimes sheets advertised for ungodly numbers of high thread counts, and you think, 'How can they possibly fit 600 threads into this little bit of sheet?'" said Fran Kozen, senior lecturer and director of undergraduate studies at Cornell's Department of Human Centered Design.

If you take two yarns and spin them together, you'll make what's called a ply yarn. "That makes a stronger yarn," said Kozen, and sheets can be made with single-, double-, triple ply yarns.

A manufacturer could use a double-ply yarn and have 100 yarns going in the weft and warp directions but count it as a 400-thread-count sheet instead of 200. "So when you see something that says it's a 600-thread-count sheet, my suspicion is that they're counting plies because I can't really see that you could fit 300 yards in it per inch," said Kozen.

The resulting sheet might have poor airflow and wouldn't necessarily feel more luxurious than 400-thread-count fabric with finer, single-ply yarn.

Quick tip: Between 300 to 400 is typically a good range for thread count. Above that, manufacturers are counting plied thread.

What's a good thread count for sheets?

You can find very nice sheets at between 300 to 400 thread counts, but you may also find soft, durable sheets outside this range. However, this isn't the only marker of quality. You'll also want to look for the type of cotton used in the sheets.

Kozen recommends looking for long-staple cotton and those labeled pima (or Supima), Peruvian, or Egyptian cotton. "When they give a name to the cotton, a varietal cotton, they're typically trying to tell you it's a premium cotton, which implies longer fibers," said Kozen. Longer cotton fibers means fewer ends that are liable to protrude, so the sheets will feel smoother and be more durable.

Keep in mind that researchers have found instances of fraud where manufacturers labeled sheets as Egyptian cotton even if they were blended with other fibers or didn't contain premium long-staple cotton. Stick with reputable brands and be suspicious of bargain-priced sheets that claim to be 100-percent long-staple, premium cotton.

Best sheets

Thread count isn't the only factor that goes into finding the perfect sheets — check out our guide to the best sheets for all types of sleepers and to the best cotton sheets, with breakdowns on thread count, material, and more.

• Best overall: L.L.Bean Percale Sheet Set (Queen) - See at L.L.Bean
• Best on a budget: Threshold Solid Performance Sheet Set (Queen) - See at Target
• Best organic cotton: Signature Hemmed Sheet Set (Queen) - See at Boll & Branch
• Best sateen: Luxe Core Sheet Set (Queen) - See at Brooklinen

Insider's takeaway

If you're purchasing 100-percent cotton sheets, thread count is only one of the factors you should consider. Be skeptical of thread counts over 400 to 500, though these may still be soft and comfortable.

You'll want to consider the weave and type of cotton in addition to thread count. Long-staple cottons tend to be softer but more expensive. You may also want different weaves depending on preference and season. A lower-thread count, crisper percale may be nicer in summer, and a cozy pick from the best flannel sheets, (which often doesn't have a thread count listed) may be what you opt for in winter.