UK King Size Bed Length: Exact Dimensions & Sizing Guide

The Exact Length of a UK King Size Bed

A UK king size bed measures 200cm (6'6") in length and 150cm (5'0") in width. That's the mattress size the entire industry builds around, from bedding manufacturers to frame suppliers, so when someone asks "how long is a king size bed," this is the number that answers it.

It's worth noting where that extra length actually comes from. A standard UK double bed is only 190cm long. King size adds 10cm to that figure, which doesn't sound like much on paper but makes a real difference for anyone over 6 feet tall who's used to their toes brushing the footboard.

Width increases too, by 15cm over a double, but length is the dimension most people underestimate when they're planning a room around a new bed.

Mattress Length vs Bed Frame Length

Here's where confusion usually starts. The 200cm figure describes the mattress, not necessarily the finished bed frame. Divan bases tend to match the mattress size closely, but frames with a headboard, footboard, or decorative detailing can add several extra centimetres to the overall footprint.

This matters most with upholstered bed frames with padded head and footboards, where the fabric-wrapped panels sit outside the mattress edge on both ends. A frame like that can easily run 10–15cm longer than the mattress it holds.

Before ordering anything, measure the full external dimensions of the frame you're considering, not just the size printed on the mattress box. Pair that frame with mattresses sized to fit a standard UK king frame and you avoid the awkward gap or overhang that comes from mismatched sizing.

How King Size Compares to Other UK Bed Lengths

Length increases in one jump across the UK size range, then holds steady from king size upward. Here's how the full lineup breaks down.

Everything up to double bed sits at 190cm long. King size is the first tier where length actually grows, and it stays at 200cm through super king and emperor. So if extra legroom is the priority rather than extra width, king size already delivers the full length gain, a super king only adds width.

Is 200cm Long Enough? Sizing for Height

The National Bed Federation recommends choosing a bed that's at least 10–13cm longer than your own height, which gives you room to stretch out fully without your feet pressing against the footboard. On that basis, 200cm comfortably suits sleepers up to around 6'3" (190cm).

Taller sleepers do have options. Some manufacturers produce extra-length frames around 215cm, and bed extenders exist for anyone who's outgrown a standard king. If you're closer to average height, though, 200cm gives a genuine margin most people never come close to using.

For the official sizing tolerances and technical standards that UK bed manufacturers follow, the National Bed Federation's regulations and standards guidance is the definitive reference.

Choosing a Frame That Doesn't Eat Into That Length

Once the mattress length is settled, the frame style decides how much of your room that 200cm actually takes up. A few categories are worth weighing against each other.

• storage bed frames that add function without extra footprint keep the external length close to the mattress size while using the space underneath for drawers or lift-up storage
• upholstered storage beds that combine padding with under-bed space suit bedrooms where both comfort and storage matter, though the padded footboard does add a few centimetres
• lightweight metal bed frames for tighter rooms tend to run closest to true mattress dimensions, which helps in smaller bedrooms or rentals
• solid wooden bed frames for a more traditional look often include a slightly deeper footboard, worth checking before you finalise room measurements

None of these choices change the 200cm mattress length itself, but they can shift the total floor space the bed occupies by a noticeable margin.

Measuring Your Room Before You Buy

Before ordering, mark out the full 150cm x 200cm footprint on your bedroom floor with tape, then add the frame's actual external dimensions on top of that. Leave at least 60cm of clearance on each side for walking space and wardrobe doors.

If floor space is genuinely tight, it's worth looking at compressed mattresses suited to flexible room layouts, which ship compact and work well with lower-profile frames that don't add much beyond the standard 200cm length.

Getting the length right is the easy part once you have the number. Getting the total footprint right, frame included, is what actually determines whether the bed fits the room the way you pictured it. For the complete range of sizes and frame styles built to these standard UK dimensions, Willsoon's full range of bed frames covers every configuration from storage to upholstered to solid wood.