Box sheets, fitted sheets and shaped sheets

Short answer: Measure the mattress length, width and depth. Depth is the figure most people forget, and it decides whether the sheet stays put.

The three measurements

Length and width are the easy ones. Depth is measured from the top edge of the mattress to the bottom, and a fitted sheet needs an edge at least as deep plus a couple of centimetres to grip underneath.

What happens if the depth is too small

The sheet pings off the corners at night. It is not the elastic that is bad, it is the edge that is too short for the mattress. See bamboo fitted sheets.

Toppers and underlays

If you have a topper, its depth has to be counted in. Two mattress layers often need a sheet with a deep edge. See bamboo sheets and bamboo box sheets.

Frequently asked questions

What is a normal mattress depth

Fifteen to twenty five centimetres. With a topper up to thirty five.

Do sheets shrink

A little in the first wash. Choose the size with that in mind.

What is the difference between a fitted sheet and a box sheet

A box sheet has a deeper edge made for tall mattresses.