Fitted Sheet Size Guide

UK bed sizes are standard, but fitted sheets have a second measurement most people forget about: depth. Get the width and length right and the depth wrong, and the sheet still will not stay on. This guide covers both, plus how to measure your own mattress if you are not sure what you have.

UK fitted sheet sizes

Every one of our fitted sheets is made to these measurements with a 40cm skirt, so the sheet measures considerably larger laid flat than the mattress it goes on. That is normal — the extra fabric is the depth, not a sizing error.

What depth fitted sheet do I need?

Depth is measured from the top surface of the mattress down to where it meets the base. It is the measurement that decides whether the sheet stays put.

• Up to 25cm — a standard sprung or foam mattress with nothing on top.
• 25cm to 30cm — a thicker pocket-sprung or hybrid mattress, or a standard mattress with a thin topper.
• 30cm to 40cm — a deep mattress, or any mattress with a proper topper on it.

A 40cm sheet fits everything in that list. It is cut to fit mattresses up to 40cm, not exactly 40cm, so on a shallower mattress the extra fabric simply gathers underneath rather than bagging at the sides. This is why buying deeper is the safer choice: too deep is invisible, too shallow pings off the corner in the night.

The mistake worth avoiding is measuring the mattress and forgetting the topper. A topper adds 5cm to 8cm, which is exactly enough to take a 30cm sheet out of range.

How to measure your mattress

1. Width and length. Measure the bare mattress corner to corner, not the bed frame. Frames are usually wider than the mattress they hold.
2. Depth. Stand a tape measure vertically at the side of the mattress, from the top surface to the base. Do not include the divan or bed frame.
3. Add the topper. If you use one, measure with it on. It counts as part of the depth.
4. Round up. If you land between two depths, take the larger sheet.

What if my bed is not a standard size?

Two variations come up often in the UK:

• European sizes are longer and sometimes narrower — a European single is 90 x 200cm rather than 90 x 190cm, and a European double is 140 x 200cm. A UK sheet will be 10cm short in length on these.
• Long or extra-long singles run to 200cm or 210cm, common in bunk beds and student accommodation.

If your mattress is one of these, measure before you buy rather than going by the name on the label. Bed size naming is not consistent between retailers, and the numbers are.

Fully elasticated or corner elastic?

Not all fitted sheets are elasticated the same way, and it makes more difference than depth on a mattress that is borderline.

Corner elastic gathers only at the four corners. The sides of the sheet hang loose, so it relies entirely on those four points to hold tension. On a deep mattress it will work its way off.

Fully elasticated runs elastic 360° around the entire skirt. The tension is spread the whole way round, which is what keeps the edge gripped under the mattress rather than creeping up the side. Every sheet we make is fully elasticated, which is also why they fold more neatly — the edge pulls into a consistent curve instead of a lumpy one.

Frequently asked questions

What size is a double fitted sheet?

A UK double fitted sheet is 135 x 190cm, or 4ft6. That is the mattress measurement — the sheet itself measures larger flat, because the skirt depth is added on all four sides.

What size is a king size fitted sheet?

A UK king size fitted sheet is 150 x 200cm, or 5ft. Note that it is longer than a double as well as wider: 200cm rather than 190cm.

What size is a single fitted sheet?

A UK single fitted sheet is 90 x 190cm, or 3ft. A small double is 120 x 190cm — same length, 30cm wider.

How deep is a deep fitted sheet?

There is no legal standard, which is why the labels are inconsistent. In practice "deep" usually means 30cm and "extra deep" means 40cm, but always check the number rather than trusting the word.

What depth fitted sheet do I need for a 25cm mattress?

Anything from 25cm upwards will fit, but 30cm or 40cm gives you room to add a topper later without buying new sheets. A 25cm sheet on a 25cm mattress has no tolerance at all.

Can I use a double fitted sheet on a small double bed?

It will go on, but it will not stay tight. A double is 15cm wider, so the excess bunches underneath and the sheet loosens as you move. A sheet cut to 120cm holds its tension properly.

How do I stop a fitted sheet coming off in the night?

Nine times out of ten it is a depth problem, not a quality problem — the sheet is too shallow for the mattress and the corners are under constant tension. Measure the mattress with the topper on and size up. Fully elasticated sheets also hold far better than corner-elastic ones.