Q&A: When buying sheets, does thread count matter?

I need new bed linens and I'm confused about thread count. Does a higher thread count indicate higher-quality sheets?

Not necessarily. Our latest tests of 23 sets of queen-size sheets reconfirmed that higher thread count doesn't guarantee better sheets. Thread count is the number of vertical and horizontal thread per square inch, and some manufacturers boost their numbers by counting plies, or the very thin yarns that make up the thread.

Among 100-percent-cotton percale sheets in our tests, some had a thread count of 400, but the highest-rated sheet had a thread count of 280.

For 100-percent-cotton sateen and twill-weave sets, the top-scoring sheet has a claimed thread count of 1,000, though some 300-thread-count sheets were better than 400- or 600-thread-count models.

The top sheets in our tests were strong, didn't shrink significantly, and fit all the mattress sizes stated on the package, even after they were washed and dried them five times. We also found that pima, Supima, Egyptian, and other long-fiber cottons are typically stronger and less likely to pill than other types of cotton.

Before you shop for new sheets, accurately measure the height of your mattress in at least two spots and away from the corners, and also measure a pad or topper. Look for sheets that are a couple of inches deeper than that measurement to allow for normal shrinkage.

—Kimberly Janeway

Essential information: Look for our upcoming review of sheets in the May 2010 issue of Consumer Reports, on ConsumerReports.org and newsstands next week, which will also feature our latest buyer's guide to mattresses. For more on mattresses, see our ratings of mattress brands and mattress stores (available to subscribers).