ONNI LONDON+ · Guides
UK mattress sizes
UK sizes are set in feet and inches and quoted in centimetres, which is why the numbers look arbitrary. Here they are, with the conversions that matter when a frame and a mattress have to meet.
The standard UK sizes
| Name | Centimetres | Feet and inches | Suits |
|---|---|---|---|
| Single | 90 x 190 | 3ft x 6ft 3 | One adult, single rooms |
| Small Double | 120 x 190 | 4ft x 6ft 3 | One adult with room, two at a squeeze |
| Double | 135 x 190 | 4ft 6 x 6ft 3 | Two adults, the UK default |
| King | 150 x 200 | 5ft x 6ft 6 | Two adults with room, and ten more centimetres of length |
| Super King | 180 x 200 | 6ft x 6ft 6 | Two adults, generous |
| Emperor | 200 x 200 | 6ft 6 x 6ft 6 | Square, and needs a room to match |
Note the length change at King. Everything below it is 190cm long, everything from King upward is 200cm. Anybody over about six foot should read that line carefully, because a Double is not short in width for most people, it is short in length.
Where UK and European sizes diverge
| UK | European equivalent | The difference | |
|---|---|---|---|
| Double | 135 x 190 | 140 x 200 | 5cm wider, 10cm longer |
| King | 150 x 200 | 160 x 200 | 10cm wider |
| Super King | 180 x 200 | 180 x 200 | The same |
A European King at 160 x 200 sits between a UK King and a UK Super King and fits neither frame properly. This catches people who buy a bed frame abroad or from an international retailer, then buy a mattress here.
US sizes are different again. A US Queen at 152 x 203 is close to a UK King but not identical, and a US King at 193 x 203 falls between Super King and Emperor. Close enough to look interchangeable on paper, far enough apart to leave gaps or overhang.
Measure the frame, not the old mattress
An old mattress may have spread or shrunk, and a frame described as a King may have been built to a different standard. Measure the internal dimensions of the frame itself, corner to corner, before ordering anything.
Also measure the way in. A 35cm deep mattress in a Super King is a substantial object, and the constraint is often the turn at the top of a staircase rather than the bedroom door.
Sizes the Perennial is made in
Every UK size, plus European King and Split King. Made to order, which is why the less common sizes are available at all rather than only the three that move fastest.
Including the sizes most makers do not carry.