What Is the Width of a King Size Bed?

The short answer on king size width

A UK king size bed is 150cm wide, which works out at 5ft. The mattress measures 150cm by 200cm, so the length runs to 6ft 6in. Those two figures are the standard used across British bed and mattress manufacturing, which is why a king size mattress bought from one retailer will sit correctly on a king size frame bought from another.

The number most people actually need, though, is not the mattress width. It is the width of the finished bed once the frame is around it. Depending on the design, expect the outer width to sit somewhere between 155cm and 170cm. A slim metal or wooden frame adds only a few centimetres each side. A deeply padded upholstered frame with a thick side rail can add closer to 10cm each side. If your room is tight, that difference matters far more than the mattress specification.

Why the mattress width and the frame width are not the same

Bed sizes in the UK are quoted by mattress size because the mattress is the interchangeable part. The frame is built around it, and every frame style handles that differently. A wooden bed with a straight side rail is close to the mattress dimension. A fabric bed with a soft, rolled edge or a winged design carries more bulk. Storage designs also change things, because an ottoman lift or drawer runner needs a solid outer casing.

When you shop for modern king size fabric beds UK, always read the overall external dimensions listed on the product page rather than assuming the bed occupies exactly 150cm. That single check prevents most of the disappointment that happens on delivery day.

How much floor space a king size bed really needs

A bed is only comfortable in a room if you can walk around it and open things near it. As a working guide, allow at least 60cm of clear walking space along any side of the bed you need to use, and closer to 75cm if that side also passes a wardrobe or a chest of drawers. Doors and drawers need room to swing or pull out, and that space cannot overlap with the space you walk in.

Take a 3m wide bedroom as an example. A king size bed with an outer width of 160cm leaves 140cm of remaining width. Split evenly, that is 70cm each side, which is comfortable. Put a bedside cabinet on each side and you lose that generosity quickly, so slimmer cabinets become the sensible choice. Narrow designs from a range of bedside cabinets UK sale options are often only 40cm to 45cm wide, which keeps the bed as the centre of the room without crowding the route past it.

Measuring your room properly before you commit

Measuring a bedroom takes five minutes and saves a great deal of trouble. Work through it in order.

First, measure the wall where the headboard will sit, at skirting level and again at waist height. Older UK houses rarely have truly square walls, and the narrower of the two figures is the one you must work to. Second, measure from that wall out to the opposite wall so you know the length available for the 200cm mattress plus the headboard depth and the footboard, if there is one. Third, mark the footprint on the floor with masking tape and live with it for a day. Walk the route to the window and the wardrobe. If the tape outline makes the room feel awkward, a smaller frame or a low footboard design will serve you better than persevering with the width.

Radiators, bay windows and chimney breasts all eat into usable width, and none of them show up on a floor plan in a helpful way. Sloping ceilings in loft conversions cause a similar problem, because the bed may fit on the floor but leave no headroom for sitting up in bed.

Getting a king size bed into the room

The mattress is the part that has to travel in one piece, and at 150cm by 200cm it is a large object to carry up a British staircase. Standard internal doorways are often around 76cm wide, so the mattress goes through on its side. Pocket sprung mattresses have limited flex, which makes tight landings and half turns on a stairwell the real obstacle rather than the doorway itself.

Frames are usually easier because they arrive flat packed in sections. If your access is genuinely difficult, a rolled mattress is the practical answer, since it is compressed and boxed for delivery and expands in the room. Browsing modern mattresses UK sale options with the delivery format in mind is worth doing before the frame is decided, because access dictates more than comfort preference does.

Bedding that fits a 150cm width

UK king size bedding is cut for the 150cm by 200cm mattress. A king size duvet is generally 225cm by 220cm, which gives you the overhang needed to stop the cover pulling off one side during the night. Fitted sheets need to match both the width and the mattress depth, and depth is where most people are caught out. A deep pocket sprung mattress with a pillow top can be 30cm or more, so a standard sheet will keep working loose.

Take note if you own bedding bought abroad. American king bedding is cut for a wider, shorter mattress, and European sizing differs again. Neither sits properly on a UK king size bed.

Choosing a frame style for the width you have

Once you know your available width, the frame style becomes a straightforward decision.

In a room with width to spare, an upholstered or leather frame with a tall headboard gives the bed presence and makes the wall feel finished. In a narrower room, a slimmer profile keeps the floor area feeling open. Wooden frames tend to be the most economical with space, and the range of king size wooden beds UK designs covers everything from clean Scandinavian shapes to solid, heavier styles. Storage designs deserve consideration too, because a king size ottoman base holds a considerable amount and can remove the need for a separate blanket box entirely.

At Furniture in Fashion we see a clear pattern in what works. People who measure first and then choose the style are happy with the result. People who choose the style first and measure afterwards often end up shuffling furniture for weeks. If you want to see how a king size frame sits alongside matching cabinets and drawers, the wider modern bedroom furniture UK sale collection makes it easier to plan the room as a whole rather than one piece at a time.

When a king size is the wrong choice

Width is not always the priority. Two sleepers who both move a lot in the night may prefer the extra shoulder room of a super king, which is 180cm wide. A single sleeper in a small second bedroom may find that a king size bed technically fits but leaves nowhere to put a lamp or a book. In a guest room used a few times a year, floor space usually matters more than sleeping width.

There is also the question of what the room has to do beyond sleeping. If you need a dressing table or a desk in the same space, giving up 30cm of bed width can transform how usable the room feels for the rest of the day.

Frequently asked questions

Is a UK king size bed the same as a US king size bed?

No. A UK king size mattress is 150cm by 200cm. A US king is wider and shorter, at roughly 193cm by 203cm. Bedding and mattresses are not interchangeable between the two standards.

How wide is a king size bed in inches?

A UK king size mattress is 60in wide and 78in long, which is 5ft by 6ft 6in.

Will a king size bed fit in a 3m by 3m bedroom?

Usually yes, provided the door does not open into the bed and the bedside furniture is kept slim. You should have roughly 70cm each side to walk in, which is comfortable for daily use.

Do I need a wider frame for a deeper mattress?

No. Mattress depth affects the height of the bed and the fitted sheets you need, not the width. A deeper mattress does mean a lower headboard will look shorter behind it, so check the headboard height above the mattress line.

Can two people share a king size comfortably?

Yes. At 150cm wide, each sleeper has 75cm, which is more than a standard single mattress width of 90cm gives one person only when compared badly, so in practice most couples find a king size generous. Light sleepers who are easily disturbed may still prefer a super king.