Fitted Sheet Pocket Depth: The Guide to a Sheet That Stays Put

What exactly is pocket depth?

Look at a fitted sheet from the side: the pocket that runs down the mattress and tucks underneath with an elastic — that is the pocket depth, measured in centimetres. A pocket that is too shallow does not reach far enough under the mattress: the elastic works at full stretch and the corners pop off at the first toss of the night. A pocket that is too deep floats and creases. Getting this measurement right is neither a luxury nor a detail: it is what decides whether your bed still looks made at 7 a.m.

The problem has become distinctly Moroccan: mattresses sold in recent years (pocket springs plus comfort foams, memory toppers) commonly reach 25 to 30 cm thick, while standard imported fitted sheets stay at a 25 cm pocket designed for 18-20 cm European mattresses. The nationwide result: sheets that pop off — and hosts who discover the phrase “pocket depth” after the purchase, not before.

Measure your mattress in 30 seconds

• Thickness: lay a rigid ruler flat on the bare mattress and measure vertically from the bed base to the top of the ruler — topper included if you use one;
• Width × length: measure the mattress, not the bed frame (a “160 bed” can hide a 158 or a 165 mattress);
• Write down all three figures: they, not the commercial name, determine your fitted sheet.

The rule of thumb: pocket depth = thickness + 5 cm, so the pocket drops well below the mattress and the elastic works relaxed. All our fitted sheets, from 90×190 to 180×200, come with a 30 cm deep pocket; above 30 cm of thickness, made-to-measure sews to your dimensions.

Why we standardised the 30 cm deep pocket

A catalogue could offer three pocket depths per size — and triple the references, the stockouts and the ordering mistakes. We chose the opposite: one single depth, 30 cm, covering 90% of today's Moroccan mattresses. On a thin mattress (16-18 cm), a 30 cm pocket simply tucks deeper under the mattress — unsightly nowhere, since everything happens underneath. On a thick mattress, a 25 cm pocket is beyond saving. The asymmetry of risk settled it.

It is also a hotel-trade choice: housekeepers want sheets interchangeable across every room. One reference per size = zero linen-room errors — the argument holds for a property manager running 25 rentals just as it does for your own cupboard.

The other reasons a fitted sheet pops off

If your pocket depth is right and the sheet still pops off, look among these suspects:

• Wrong nominal size: a 160×200 sheet on a 165×205 mattress works under permanent tension — measure the actual mattress;
• Shrinkage: unstabilised cotton loses 3-5% at the first hot wash: 200 cm becomes 192. Stabilised polycotton moves by 1-2% at most (the comparison here);
• Tired elastic: after 100+ high-temperature washes, the elastic cooks — if the fabric still looks good, it is the elastic's age talking;
• Partial elastic: entry-level sheets are elasticated at the corners only; a full all-around elastic (our finish) holds evenly.

Special cases: upholstered bases, adjustable beds, twin mattresses

• Visible upholstered base: the fitted sheet dresses the mattress only; if you want to cover the base, add a valance — not a deeper pocket;
• Adjustable electric beds (160 as 2×80): two independent 80×200 fitted sheets, never one shared 160 that would block the articulation;
• Twin mattresses pushed together: one shared fitted sheet accentuates the centre gap; prefer two fitted sheets + one unifying topper + one shared flat sheet;
• Built-in riad beds: measure everything, bench overhangs included — this is workshop made-to-measure territory, detailed on our riad page.

Frequently asked questions