Sheet shopping has become something of a numbers game. And it’s not the numbers in the price that are attracting attention, it’s the thread count.

The higher that number, the softer the sheet, right? Not necessarily. Characteristics such as fabric and weave can add significantly to a sheet’s quality and tactile appeal. In fact, in certain combinations, the fabric and weave can make a lower thread count feel softer than a higher thread count made of a different fiber in a different weave.

What’s most important to consider is that thread counts are sometimes overstated on a sheet’s packaging. And that’s something that has even caught the attention of the Federal Trade Commission’s Bureau of Consumer Products.

What exactly is thread count? It’s the number of horizontal and vertical threads in 1 square inch of fabric. A 400-thread-count sheet will have 400 threads in that square inch. The plies, on the other hand, are what make up the yarn, and there are multiple plies in the yarn. When that number is used on packaging to describe a sheet, it can be misleading to consumers who have been trained to equate a high number with high quality. For instance, a sheet labeled 400 two-ply, or “twisted,” yarns is actually a 200-thread- count sheet.

The FTC has now taken steps to prevent this practice of thread- count exaggeration. It stated that “multiplying by ply is inappropriate” for a sheet maker, and in doing so the manufacturer is “stating an inflated thread count.” The FTC advised sheet makers to clearly label their products with the thread count, regardless of single or plied components, and then provide additional information on the yarn’s ply.

Consumers are warned to read the package carefully and let the price be a warning sign. If it looks like you’re getting the deal of a lifetime, it may be too good to be true.

“People have been trained to look to the number on a package of sheets as an immediate indicator of quality, but with today’s manufacturing capabilities it’s not that simple,” said Leslie Gillock, vice president of brand management for Wamsutta sheets, which supports the FTC’s recommendation.

“With the variety of fibers and different weaving techniques available to manufacturers, sheets come in a broad range of choices in softness, durability, crispness and care, so consumers should look carefully at the characteristics of a sheet,” Gillock said. “Above all, don’t be misled by high count two-ply sheets. Feel the sheet itself, and buy the one that’s best for you.”

Fabric is equally important in determining the sheet’s feel. A long-staple, premium cotton -; such as Egyptian or Pima cotton -; will create a softer sheet than a short-staple cotton or even a combed cotton, where shorter fibers have been “combed” away. Sheets made with a cotton-polyester blended fabric or with linen will be crisp to the touch, though the latter is likely to require dry cleaning and be more expensive in laundering. The benefits of man-made fibers such as polyester are that they wrinkle less and look sharp on the bed.

Lastly, pay attention to the weave. A percale’s smooth weave makes for a smooth sheet. A sheet made in a pinpoint weave boasts crispness. And a sateen weave adds softness and a lustrous look.

The best test, though, is touch. Your hands will tell you in an instant if the numbers add up to a sheet that’s right for you.