A deep-pocket mattress generally is 14 to 18, or 20 inches deep, and locating sheets to match requires a bit of sleuthing. But if you go armed with the measurements of the mattress and understand how to read the sheet label, then you’ll be prosperous.
Measure and Be Sure
Measure from the top of the mattress to the peak of the box spring. This measurement is the thickness of the mattress. Measure the amount of the bed, from the top border to the foot, across the surface of the mattress. Record such as the bed span. Measure from the left border, across the top of the mattress to the ideal side and record this as the bed width. Both of these measurements determine the size of the sheet. Check the sheet package label first for bed size, then check the sheet package label for the thickness of the mattress; it’ll be written on the label. The tuck section below the mattress isn’t considered part of the sheet pocket.