Quick answer: Standard UK mattress sizes in centimetres are small single 75 × 190, single 90 × 190, small double 120 × 190, double 135 × 190, king 150 × 200 and super king 180 × 200. Emperor beds are usually around 200 × 200 cm but vary by brand. The first figure is the width, the second the length.
British beds are still sold under names and foot measurements (“a 4ft 6 double”) even though manufacturers make them to metric sizes. This chart gives the centimetre figures retailers actually use, the exact inch equivalents and how UK sizes compare with European and American beds. For other room and furniture measuring jobs, see our home measuring guides.
UK bed size chart in cm and inches
Every standard UK adult size is either 190 cm or 200 cm long; the width is what changes. The imperial names are nominal: a 4ft 6in double would be 137.16 cm if converted exactly, but the metric mattress is made at 135 cm. The inch column below is the exact conversion of the metric size.
| UK size | Width × length (cm) | Exact inches | Nominal imperial name | Surface area |
|---|---|---|---|---|
| Small single | 75 × 190 cm | 29.5 × 74.8 in | 2ft 6in × 6ft 3in | 1.43 m² |
| Single | 90 × 190 cm | 35.4 × 74.8 in | 3ft × 6ft 3in | 1.71 m² |
| Small double | 120 × 190 cm | 47.2 × 74.8 in | 4ft × 6ft 3in | 2.28 m² |
| Double | 135 × 190 cm | 53.1 × 74.8 in | 4ft 6in × 6ft 3in | 2.57 m² |
| King | 150 × 200 cm | 59.1 × 78.7 in | 5ft × 6ft 6in | 3.00 m² |
| Super king | 180 × 200 cm | 70.9 × 78.7 in | 6ft × 6ft 6in | 3.60 m² |
| Emperor (varies) | about 200 × 200 cm | 78.7 × 78.7 in | about 6ft 6in × 6ft 6in | 4.00 m² |
To convert any other measurement on a bed listing, the cm to inches converter and cm to feet converter give exact figures.
What size is a UK double bed in cm?
A UK double mattress is 135 cm wide and 190 cm long. That is 4ft 6in by 6ft 3in in the traditional naming. A small double, sometimes sold as a “queen” by UK retailers, is 120 × 190 cm, so check the centimetre figure rather than the name when you are buying a mattress for an existing frame.
What is the difference between a king and a super king?
A super king is 30 cm wider than a king: 180 cm against 150 cm, with both 200 cm long. Moving from a double to a king adds 15 cm of width and 10 cm of length. Moving from a king to a super king adds a full 30 cm, which is why super kings are often made as two single-width halves zipped together.
How much width does each sleeper get?
Two people on a UK double get 67.5 cm each, which is less than a 75 cm small single. Halving the width is a simple way to compare sizes for couples.
| Bed shared by two | Width per person | Compared with |
|---|---|---|
| Small double (120 cm) | 60 cm | 15 cm narrower than a small single |
| Double (135 cm) | 67.5 cm | 7.5 cm narrower than a small single |
| King (150 cm) | 75 cm | Same as a small single |
| Super king (180 cm) | 90 cm | Same as a single |
Are UK bed sizes the same as European and US sizes?
No. European beds are generally 200 cm long and come in different widths, and US beds are based on whole inches. Bedding and mattresses from one system rarely fit a frame from another, which matters if you buy from an overseas retailer or a Scandinavian furniture brand.
| Size | UK (cm) | Typical EU (cm) | US (inches) | US (cm) |
|---|---|---|---|---|
| Single / twin | 90 × 190 | 90 × 200 | 38 × 75 | 96.5 × 190.5 |
| Double / full | 135 × 190 | 140 × 200 | 54 × 75 | 137.2 × 190.5 |
| King / queen | 150 × 200 | 160 × 200 | 60 × 80 (queen) | 152.4 × 203.2 |
| Super king / king | 180 × 200 | 180 × 200 | 76 × 80 (king) | 193 × 203.2 |
Note the naming trap: a US queen (152.4 cm wide) is close to a UK king, and a US king (193 cm) is wider than a UK super king.
What size is a cot mattress in the UK?
A standard UK cot mattress is 60 × 120 cm and a cot bed mattress is 70 × 140 cm. Cots are made in other sizes too, so measure the inside of the cot base rather than relying on the label. The NHS advises a firm, flat mattress for babies, and the mattress should fit the cot snugly without gaps around the edges; the Lullaby Trust publishes detailed safer-sleep guidance.
How big does a bedroom need to be for each bed size?
A practical rule is to keep at least 60 cm of clear floor along each side you get in from and at the foot of the bed. On that basis a double pushed against one wall needs a room roughly 195 cm wide (135 + 60) and 250 cm long (190 + 60), while a king with access on both sides needs about 270 cm (150 + 60 + 60) by 260 cm. Remember that frames and headboards add several centimetres to the mattress size.
Frequently asked questions
What size is a single bed in the UK in cm?
A UK single mattress is 90 cm wide and 190 cm long, traditionally called 3ft by 6ft 3in. A small single is 75 by 190 cm.
Is a UK king size the same as a US king?
No. A UK king is 150 by 200 cm, close to a US queen at 152.4 by 203.2 cm. A US king is 193 by 203.2 cm, wider than a UK super king.
Will a European 140 x 200 mattress fit a UK double bed?
Usually not. It is 5 cm wider and 10 cm longer than a UK double at 135 by 190 cm, so it will overhang or not fit inside the frame.
Are bed sizes exact?
Not to the millimetre. Mattresses are made to nominal sizes with small manufacturing tolerances, and the international standard ISO 24975 sets out how beds and mattresses should be measured. Measure your frame if the fit is tight.
Sources
- National Bed Federation, the UK bed manufacturers’ trade association
- BSI: ISO 24975:2026 Furniture. Beds and mattresses. Methods of measurement and recommended tolerances
- NHS: Reduce the risk of sudden infant death syndrome
- Soak&Sleep: Mattress and bed size guide (UK, EU and cot bed sizes)
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