What the Size of King Size Bed?

The Measurement You Came For

A king size bed in the UK is 150cm wide by 200cm long. In imperial terms that is 5ft by 6ft 6in. Those figures describe the mattress, so the bed frame itself will be a little larger, usually adding 5cm to 15cm on the width and length depending on how the frame is built.

King sits between the double at 135cm wide and the superking at 180cm wide. It is 15cm wider and 10cm longer than a double, and that extra length is often the deciding factor for taller sleepers who assume they need a wider bed when what they actually need is a longer one.

Where King Fits in the UK Size Range

The main UK sizes run in a predictable sequence. A single is 90cm by 190cm. A small double is 120cm by 190cm. A double is 135cm by 190cm. A king is 150cm by 200cm, and a superking is 180cm by 200cm.

The pattern is worth noticing: the jump from double to king brings both extra width and, for the first time, extra length. A double at 190cm long leaves a person of six feet with very little room at the feet once pillows and a headboard are accounted for. At 200cm, a king solves that.

For two adults sharing, a king gives each person 75cm of width. That is less than the width of a small single, which puts the size in perspective: a king is comfortable rather than expansive, and couples who find themselves negotiating for space at 135cm will feel the improvement immediately without needing to go to a superking.

UK King Versus US King

This is where confusion creeps in, especially when buying bedding or reading advice written abroad. A US king measures roughly 193cm by 203cm, which is far wider than a UK king and closer to a UK superking in width. A US queen at around 152cm by 203cm is the closest American equivalent to a UK king.

The practical consequence is that bedding sizes do not translate. A duvet cover bought overseas and labelled king will not fit a UK king mattress properly, and a fitted sheet will either strain or sag. Always buy UK sized bedding for a UK bed and check the centimetre measurements on the packaging rather than the size name alone.

Frame Size Against Mattress Size

When a listing says king size, it is telling you the mattress fits a 150cm by 200cm space. It is not telling you how much floor the bed takes up. Slim metal and wooden frames add only a few centimetres each side. Upholstered frames with padded rails can add 10cm or more, and frames with a footboard extend the length as well.

Headboard height is the other measurement people overlook. A tall headboard behind a bed positioned under a window or against a sloping ceiling can be a problem, and it also changes the proportions of the room. Our modern king size leather beds UK sale listings give overall height as well as width and length, and it is worth reading both before you commit.

If the bedroom has limited natural light, a reflective finish helps. Our modern king size high gloss beds UK range bounces light around a room, which can make a large frame feel less heavy than a matt finish in the same colour.

The Room a King Size Bed Needs

Take the frame width, not the mattress width, and add walking space. Around 60cm each side is comfortable, and 45cm is workable if one side is used less. That puts a king bed with access on both sides at roughly 2.8m of wall to wall width, before bedside cabinets.

At the foot of the bed, allow at least 70cm if there is a wardrobe or chest of drawers on that wall, since drawers and doors need clearance to open fully. In a room where the bed must sit against a side wall, plan on making the bed from the foot end and accept that changing a duvet takes a little longer.

Most UK main bedrooms in newer homes will take a king, but not always with furniture on all four walls. It often comes down to choosing between a larger bed and a freestanding wardrobe. Using height rather than width is the way out of that choice, and our modern wardrobes UK sale range includes tall designs with narrow footprints for exactly that situation.

Mattresses in King Size

King mattresses come in every construction: pocket sprung, open coil, memory foam, hybrid and rolled foam. At this width, independent support matters more than it does on a single, because two people of different weights are loading the same surface. Pocket springs work individually, so movement on one side transmits less across the bed.

Depth runs from roughly 18cm to 30cm and affects both comfort and the finished height of the bed. Combine base height and mattress depth to work out where the sleeping surface will sit, and aim for the top of the mattress to fall between 55cm and 65cm from the floor for easy getting in and out.

Access is worth checking before ordering. A one piece king sprung mattress is heavy and barely flexes, so measure the stair turn and doorways. Rolled mattresses from our mattresses UK sale range arrive compressed and expand in the room, which sidesteps the problem in older houses with tight landings.

Bedding and Pillows for a King

A UK king duvet is around 225cm by 220cm. Fitted sheets are cut for a 150cm by 200cm mattress, with pocket depths that vary, so check the depth if your mattress is more than about 25cm deep.

Pillows are a small detail that changes how the bed looks. Two standard pillows measure roughly 150cm side by side, which matches a king mattress almost exactly. That is why a king bed dressed with two standard pillows looks balanced, while the same pillows on a superking leave a visible gap.

For a throw, around 220cm by 240cm gives full coverage with an even fall on both sides. Anything under 200cm wide is best folded across the foot of the bed instead.

Furnishing Around a King Bed

At 150cm wide, the bed is the anchor of the room and everything else should relate to it. Matching cabinets either side give the arrangement symmetry, and keeping the cabinet top level with or just below the mattress top puts the lamp and a glass of water within easy reach. Our modern bedside cabinets UK sale range includes both slim and wider designs, and the slim ones are often the better choice once you have committed the floor space to a king.

A rug under the lower two thirds of the bed softens the floor and defines the sleeping area. Size it to extend at least 60cm beyond each side of the frame, otherwise it reads as too small for the room.

Buying a King Size Bed From Us

We carry king size frames in fabric, leather, wood, metal and high gloss, with mattresses and bedroom storage to match. Every listing at Furniture in Fashion includes the external frame measurements so you can plan the room accurately rather than working from the mattress size alone. We offer free delivery to most UK mainland postcodes, and Returns are available up to 30 days.

Is a King the Right Upgrade?

Most people arrive at the king size question from one of two directions, and the right answer differs.

If the complaint is feet reaching the end of the mattress, the length is doing the work and a king is the straightforward fix. Going from 190cm to 200cm resolves it for anyone up to roughly six feet four, and the extra 15cm of width comes as a bonus rather than the point.

If the complaint is being crowded by a partner, look carefully at the room before assuming a king solves it. A king gives each sleeper 75cm, which is 7.5cm more each than a double. That is a real improvement but a modest one, and where the room can take 180cm a superking gives 90cm each and settles the issue properly. Where the room cannot, a king with a pocket sprung mattress that limits motion transfer often achieves more than the extra width would.

A third case is worth mentioning: rooms where a double already fits comfortably with space to spare. Here a king simply makes better use of the floor area, and the change tends to make the room feel more considered rather than more full, provided the walkways stay above 60cm.

Common Mistakes When Buying a King

Three errors account for most problems. The first is measuring the room but not the route. A king rail is over 200cm long, and the stair turn is where it stops.

The second is buying the mattress and the frame separately without checking depth. A 32cm mattress on a frame with a low side rail sits proud of the rail, which looks unfinished and makes fitted sheets harder to keep in place. Conversely, a shallow 18cm mattress in a frame designed for a deeper one leaves the rail standing high around the edges.

The third is forgetting the vertical measurement. Frame height plus mattress depth should land between 55cm and 65cm for comfortable sitting, and bedside cabinets should finish level with or slightly below the top of the mattress. Buying the bed first and the cabinets later is how people end up with a bedside surface at chest height.

Frequently Asked Questions

What are the exact dimensions of a UK king size bed?

The mattress is 150cm wide by 200cm long, equivalent to 5ft by 6ft 6in. The frame will be slightly larger, so check the external measurements on the product listing.

Is a king size bed big enough for two adults?

For most couples, yes. Each person has 75cm of width, which is comfortable for sleeping. Those who want noticeably more separation tend to move up to a superking at 180cm wide.

Will a king mattress fit a double bed frame?

No. A double frame is built for a 135cm by 190cm mattress, so a king mattress would overhang on the width and the length. The mattress must match the frame’s internal dimensions.

Is a UK king the same as an American king?

No. A US king is around 193cm by 203cm, much wider than the UK king. A US queen at about 152cm wide is the nearest equivalent to a UK king.

What size room suits a king size bed?

A room around 3m by 3.4m allows a king bed with walking space on both sides and bedside cabinets. Smaller rooms can take one, though usually with one side of the bed against a wall.