UK Bed Sizes Explained: What Duvet, Sheet and Pillowcases You Actually Need
Bed sizes in the UK are named, not measured, which is why so many people end up with a duvet that hangs off one side and a fitted sheet that pings off a corner at 3am. This guide gives you the actual numbers for each size, and answers the two questions that cause the most returns: what depth of fitted sheet you need, and which pillowcase size to buy.
The four UK bed sizes
These are the mattress widths the names refer to:
| Bed size | Mattress width | Duvet you need |
|---|---|---|
| Single | 3 ft (90 cm) | 135 x 200 cm |
| Double | 4'6" (135 cm) | 200 x 200 cm |
| King | 5 ft (150 cm) | 230 x 220 cm |
| Super King | 6 ft (180 cm) | 260 x 220 cm |
Notice that the duvet is always considerably wider than the mattress. That difference is the drop — the part that hangs over the sides and stops your partner stealing it. A Double duvet at 200 cm on a 135 cm mattress gives roughly 32 cm of drop each side.
The King and Super King trap
King and Super King duvets are both 220 cm long, but 230 cm and 260 cm wide respectively. If you upsize your bed from King to Super King and keep the old duvet, the length still fits — so it feels almost right — while you lose 15 cm of drop on each side. It is the most common reason people tell us their new bed "feels colder".
Fitted sheets: width is easy, depth is not
The width of a fitted sheet is decided for you by the bed size. Depth is the part worth thinking about, and it is where most sizing mistakes actually happen.
Mattresses have got deeper over the last twenty years. A traditional sprung mattress might be 20 cm; a modern pocket-sprung or memory-foam mattress with a pillow top can be 30 cm or more, and that is before you add a topper. A fitted sheet cut for a shallow mattress will technically go on a deep one, but it will sit under tension and work its way off a corner during the night.
Our standard fitted sheets are cut for mattresses up to 35 cm — around 14 inches — deep. That covers the large majority of UK mattresses, pillow-tops included. From 15 inches upwards we tailor a deeper skirt, which you can choose when you build your set.
Measure before you buy. Put a tape measure vertically against the side of the mattress, from the base to the top surface. Include a topper if you use one permanently — it is part of the depth as far as the sheet is concerned. Do not measure the bed frame.
If your measurement comes in over 35 cm, take the deeper option. There is no penalty for going deeper than you need: the extra fabric simply tucks further under the mattress. A sheet cut shallower than your mattress, on the other hand, will never stay put.
Pillowcases: Standard or King Size
Two pillowcase sizes cover almost every UK bed:
- Standard — the usual rectangular pillow, right for Single, Double and most King beds.
- King Size — longer, and the natural choice on a Super King, where two standard pillows leave a visible gap in the middle of a 180 cm headboard.
This is aesthetic as much as practical. Two standard pillows on a Super King look marooned; two king-size pillows fill the width properly. If you sleep with four pillows, the usual arrangement is two king-size at the back and two standard in front.
How many pillowcases come in a set
Our bedding sets include two pillowcases as standard, except Single sets, which include one. You can add a second pair if you sleep with four.
A quick checklist before you order
- Confirm your bed size by measuring the mattress width, not the frame.
- Measure mattress depth vertically, including any permanent topper — under 35 cm takes the standard sheet.
- Choose your duvet size from the table above — match the bed, not the duvet you already own.
- Pick Standard pillowcases, or King Size if you are dressing a Super King.
If you would rather see it than calculate it, you can build a complete set and pick the size once — the sheet, duvet cover and pillowcases all follow from it, so the pieces cannot end up mismatched.
