Deep pocket sheets

Deep pocket sheets are fitted sheets cut with taller corner pockets, usually starting around 15 inches and going up from there, to fit over a thicker mattress. Standard fitted sheets are typically cut for mattresses around 8 to 10 inches deep, which is often not enough once a mattress topper or a taller innerspring mattress is added on top.

This matters more for tall sleepers than it might seem, since taller people often choose thicker, more supportive mattresses and add toppers for extra length-adjusted comfort, both of which increase the total height the fitted sheet needs to cover. A sheet that is even an inch or two too shallow will pop off the corners repeatedly through the night.

Extra deep pocket sheets go further still, often covering 18 to 22 inches, and are worth checking specifically if a mattress plus topper combination measures unusually tall. Always check the listed pocket depth against the actual height of your mattress and topper together, not just the mattress alone, since guessing is the most common reason deep pocket sheets still end up too shallow.