Fitted Sheet Depth Guide

A fitted sheet that will not stay on is the single most common reason a bedding order comes back. Almost every time, the cause is depth, not quality.

What actually determines whether a sheet stays on

Three numbers matter and they have to be read together: the mattress height, the topper thickness, and the pocket depth of the sheet you are buying.

A standard mattress is 20–25 cm deep. Add a 5 cm topper and you are at 30 cm. Most cheap fitted sheets in the market are cut at 25–28 cm pocket depth — which is fine on a bare mattress and hopeless once a topper is fitted.

The number that actually protects you

Specify pocket depth at least 8 cm more than your total bed height. For a 30 cm bed assembly, buy 38 cm pockets. That extra margin is what absorbs washing shrinkage over the product's life.

We cut our fitted sheets at 38 cm as standard for exactly this reason. If your market is mattress-topper heavy — North America and the Gulf both are — going deeper is the cheapest way to cut your return rate.

What else to check before you buy

• 360° elastic, not four corner patches. Corner patches are the second most common cause of pop-off.
• Shrinkage testing. A sheet that loses 5% in the first wash can lose the depth margin you paid for.
• Whether the pocket is stitched flat or gathered. Gathered corners hold tension better over time.

Ask any supplier for their shrinkage figure and their pocket depth in writing. If they cannot produce both numbers, they have not tested it.