A bed can look perfectly sized in a product photo, then leave a real bedroom feeling cramped once the frame, headboard and bedside furniture are in place. This UK bed size guide sets out the standard mattress dimensions and the practical checks worth making before you order, especially when storage, walkways and delivery access matter.
UK bed size guide: standard mattress dimensions
UK bed sizes are based on the size of the mattress rather than the outer measurements of the bed frame. An upholstered frame, sleigh bed or divan base can extend beyond these dimensions, sometimes by several centimetres on each side. Always check the product specification for the complete bed footprint.
| UK bed size | Mattress size in cm | Approximate size in feet and inches | Best suited to | | — | — | — | — | | Small single | 75 x 190 cm | 2 ft 6 in x 6 ft 3 in | Children, narrow rooms and compact guest spaces | | Single | 90 x 190 cm | 3 ft x 6 ft 3 in | One adult, teenagers and standard guest rooms | | Small double | 120 x 190 cm | 4 ft x 6 ft 3 in | One person wanting extra space or compact couples’ rooms | | Double | 135 x 190 cm | 4 ft 6 in x 6 ft 3 in | Couples, larger single sleepers and family homes | | King size | 150 x 200 cm | 5 ft x 6 ft 6 in | Couples wanting more personal sleeping space | | Super king | 180 x 200 cm | 6 ft x 6 ft 6 in | Large bedrooms and couples who prioritise maximum room |
The length changes at king size and above. A king or super king mattress is 10 cm longer than a single or double, which can make a noticeable difference for taller sleepers. It also means fitted sheets, mattress protectors and bedding should be bought for the exact size rather than guessed from the frame name.
Choosing a bed size for the people using it
For a child moving out of a cot bed, a small single is often a sensible space-saving choice. It gives enough room for younger children while leaving floor space for play, drawers or a wardrobe. A standard single is more versatile for older children and teenagers, particularly if the room will need to work as a guest room later on.
A small double is a useful middle ground that is often overlooked. At 120 cm wide, it offers one sleeper much more room than a single without taking up the same floor area as a double. It can also work for occasional two-person use, although it gives each person only 60 cm of width. For everyday couples, that may feel tight.
A double remains a popular choice because it fits many UK bedrooms and has widely available bedding. However, its 135 cm width gives each sleeper 67.5 cm – less personal space than a standard single bed. If the room allows it, moving up to a king size gives an extra 15 cm of width and 10 cm of length. That extra room is often worthwhile for couples, taller people or anyone sharing the bed with a child or pet.
A super king provides generous sleeping space, but it needs a genuinely large room to feel practical. It is an excellent option where comfort is the priority, yet it can make a bedroom difficult to move around if wardrobes, drawers or radiators are close to the bed area.
Think beyond the mattress measurement
The mattress size tells only part of the story. Divan beds are usually close to mattress dimensions, but an upholstered frame may have wide side rails, a deep footboard or a padded headboard. Sleigh beds are particularly worth measuring carefully because their shaped head and foot ends can add length.
If you are replacing an existing bed, measure the available space rather than assuming the new frame will fit in the same position. Also measure doorways, staircases, landings and tight turns. A large bed may arrive in separate parts, but a bulky headboard or a one-piece mattress still needs a clear route into the room.
Plan the room, not just the bed
A bed should leave enough space to use the room comfortably. As a practical starting point, aim for around 60 cm of clear walking space along the exposed sides of the bed and at the foot. This is not always possible in a compact flat or box room, but it is a useful target when comparing sizes.
Consider where doors open, including wardrobe doors. A hinged wardrobe placed too close to the bed can become awkward to use, while drawers need clear floor space in front of them. If the room is narrow, sliding-door wardrobes or an ottoman bed may make better use of the layout than bedside drawers and a drawer-storage divan.
For landlords and furnished rental properties, repeatable sizing can make replacement bedding and mattresses easier to manage. Standard singles and doubles are often the most straightforward choices for smaller bedrooms, while a king size can add appeal in a main bedroom where the floor space supports it.
Storage beds: match the opening style to your room
Storage is one of the strongest reasons to choose a particular bed design, but it affects how the room works day to day. Ottoman storage beds lift from the end or side and use the full area beneath the mattress. They are well suited to bedding, seasonal clothing and items you do not need every morning.
An ottoman needs room above and around the bed for the mattress platform to lift safely. Check the opening direction before ordering, particularly if the bed sits below a window, near a low ceiling feature or beside tall furniture. Side-opening ottomans can be practical in long, narrow rooms, but only if the lifting side remains clear.
Drawer divans provide easier access to smaller items without lifting the mattress. Their trade-off is that drawers need space to open, so they are not ideal where the bed sits tightly against a wall or another piece of furniture. A standard divan with no drawers may be the better fit when the bedroom is compact but the bed needs to sit close to the edge of the room.
Choosing the right mattress for the size
The mattress must match the bed size exactly. A UK double mattress should measure 135 x 190 cm, while a king size mattress should measure 150 x 200 cm. European sizes can look similar but are not always interchangeable. For example, a 160 x 200 cm mattress is wider than a UK king size, so it will not fit a standard UK king frame correctly.
Mattress depth matters too. A deeper mattress can make an upholstered headboard look lower and may affect how fitted sheets sit around the corners. For ottoman beds, check any stated maximum mattress weight, especially if you are choosing a thick pocket-sprung or memory foam model. The lift mechanism needs to be suitable for the mattress you intend to use.
When selecting comfort, size and support should work together. A larger bed gives partners more room to move, but it cannot compensate for a mattress that is too soft, too firm or poorly suited to your usual sleeping position. If two people have different preferences, a king or super king can make it easier to choose a mattress with enough space for undisturbed sleep.
A practical measuring checklist before ordering
Before choosing a size, measure the wall where the headboard will sit, the room width at the widest and narrowest points, and the distance to wardrobes, windows and doors. Marking the proposed bed footprint on the floor with masking tape can make the decision much clearer than relying on a tape measure alone.
Include the frame’s full dimensions, not only the mattress dimensions. Then check the planned clearance for opening drawers, lifting an ottoman, changing bedding and walking around the bed. Finally, confirm that the mattress, base and headboard can be delivered through the property without difficulty.
The best bed size is not simply the largest one that fits. It is the one that gives you comfortable sleep, useful storage and a bedroom you can still move around with ease. AAA Furniture UK Ltd offers bed styles across the main UK sizes, helping you choose a practical combination of frame, storage and mattress for the space you have.