King Size Mattress Dimensions: Everything You Need To Know

by | May 25, 2026 | Buying Guides | 0 comments

King size mattress and upholstered divan bed styled in a neutral modern bedroom with layered pillows, soft lighting and warm wooden furniture.

King size mattresses are becoming increasingly popular as people prioritise extra sleeping space and comfort, and once you understand the size and how it actually feels to sleep on, it makes perfect sense.

If you’ve ever shared a double bed and found yourself negotiating space in the middle of the night, a king size bed size is usually the point where things start to feel properly comfortable.

But choosing a king size mattress isn’t just about upgrading for space. There are a few details that tend to catch people out, from room clearance and mattress depth to the difference between UK and European king sizes, and whether a zip and link option might work better for your home. We’ll walk through all of it here, clearly and honestly, so you know exactly what you’re getting before you buy.

King size mattress size: the quick answer
A standard UK king size mattress measures 150cm wide by 200cm long (5ft x 6ft 6in), and it’s this extra space that makes all the difference. Compared to a standard UK double mattress, you get an extra 15cm of width and 10cm of length, which gives each person around 75cm of sleeping space for a noticeably more comfortable sleep.
King size mattresses are available in all constructions, including pocket sprung, memory foam, hybrid, latex, and natural fillings, and in tensions from soft through to extra firm. At Land of Beds, you’ll find a full range of king size mattresses across every style and price point, all with free UK delivery on orders over £100.

What are the dimensions of a UK king size mattress?

Centimetres
150 × 200
Width × Length
Feet & inches
5ft × 6ft 6in
Width × Length
Inches
59in × 79in
Width × Length
Metres
1.5m × 2.0m
Width × Length
Millimetres
1500 × 2000
Width × Length
Area
3.0m²
Total sleeping surface
Important: mattress vs bed frame dimensions
These dimensions refer to the mattress only. Bed frames are typically slightly larger, often adding around 5 to 10cm on each side depending on the design, side rails, and headboard style. It is always worth checking the full bed frame dimensions before ordering. For example, a king size mattress on a divan base will take up a different amount of space compared to the same mattress in a bed frame with wider rails.

How does a king size mattress compare to other UK sizes?

All standard UK mattress sizes in a single table, with the king size highlighted for easy comparison.

Size Width × length (cm) Width × length (ft/in) Per person (couples) Compared to king size
Small single 75 × 190cm 2ft 6in × 6ft 3in — 75cm narrower
Single 90 × 190cm 3ft × 6ft 3in — 60cm narrower
Small double 120 × 190cm 4ft × 6ft 3in 60cm each 30cm narrower, 10cm shorter
Double 135 × 190cm 4ft 6in × 6ft 3in 67.5cm each 15cm narrower, 10cm shorter
King size 150 × 200cm 5ft × 6ft 6in 75cm each —
European king 160 × 200cm 5ft 3in × 6ft 6in 80cm each 10cm wider
Super king 180 × 200cm 6ft × 6ft 6in 90cm each 30cm wider
Small emperor 200 × 200cm 6ft 6in × 6ft 6in 100cm each 50cm wider
Emperor 215 × 215cm 7ft × 7ft 107.5cm each 65cm wider, 15cm longer

How much space does a king size mattress give each person?

The most helpful way to think about king size mattress dimensions isn’t in total centimetres, it’s in personal space. On a king size mattress, each person gets around 75cm of sleeping width.

That’s the point where most people can sleep comfortably without constantly noticing their partner’s movements. On a double, where each person has around 67.5cm, the difference sounds small but in practice it often isn’t. That slightly reduced space is usually where movement starts to be felt more easily, which is why couples tend to notice the upgrade straight away.

The extra length is talked about less, but it matters just as much for the right person. A king size mattress is 200cm long compared to 190cm for a standard double, which makes a noticeable difference for taller sleepers. As a rough guide, a double tends to suit people up to around 5ft 11in, while a king size is more comfortable up to around 6ft 3in. If you or your partner are over 6ft, the extra length alone can make a real difference to how well you sleep.

Mattress size Per person width Equivalent to What this means in practice
Double (135cm) 67.5cm each Less than a standard single Movement is more noticeable, and couples are more likely to disturb each other.
King size (150cm) 75cm each More space than a double, but less than a standard single each The point where most couples start to sleep more comfortably without regularly disturbing each other.
Super king (180cm) 90cm each Roughly equivalent to a standard single each More generous personal space, with less awareness of movement during the night.
Small emperor (200cm) 100cm each Wider than a standard single each Very spacious. Movement is rarely noticed and each sleeper has plenty of room.

What room size do you need for a king size mattress?

This is the part most people don’t think about until it’s too late: whether a king size mattress will actually work in your room. It’s very easy to fall in love with the idea online, but the reality comes down to space.

The mattress itself measures 150 × 200cm, but the room you need is always more than that. You need space to walk around the bed comfortably, room to open drawers if you’re choosing a storage bed, and enough clearance to access wardrobes without everything feeling squeezed in. It’s the difference between a bedroom that feels calm and one that feels slightly cramped every time you move around it.

The clearance rule
Allow at least 60cm of space on each side of the bed that you regularly use, and around 90cm on the main side where you get in and out. If the bed does not sit against a wall, aim for around 90cm at the foot as well.

As a general guide, a king size bed works best in a room of around 3.5m × 3.5m. This gives you enough space around the mattress for comfortable movement without the room feeling tight.
Mattress size Mattress dimensions Recommended minimum room Notes
Double 135 × 190cm 3.0m × 3.5m A versatile option for smaller bedrooms
King size 150 × 200cm 3.5m × 3.5m Check wardrobe doors and walkways open comfortably
European king 160 × 200cm 3.5m × 3.5m Wider than a UK king size, so check clearance carefully
Super king 180 × 200cm 4.0m × 4.0m Measure carefully before ordering, as this is a large mattress

Before you order, take a moment to measure your room at its widest points. It’s also worth noting where doors and windows sit, and checking that wardrobe or ensuite doors can open properly once the bed is in place.

A king size that technically fits on paper but leaves no space to move around it can end up making the room feel more cramped, not better.

Mattress depth and why it matters

Width and length tend to get most of the attention, but mattress depth matters just as much, just for slightly different reasons.

Mattress depth is simply how tall the mattress is from base to sleeping surface. It’s usually measured in centimetres and can range from around 15cm for basic rolled mattresses up to 35cm or more for premium, hand-crafted designs with deeper comfort layers.

It’s one of those details that’s easy to overlook, but it has a real impact on how the mattress feels and how it works in your space. There are three main reasons it matters

Bedding fit
Fitted sheets and mattress protectors need to accommodate the depth of your mattress as well as any topper you’re using. For example, a 30cm mattress with a 5cm topper will usually need sheets designed for at least 35cm depth. Standard fitted sheets often fit mattresses up to around 25 to 28cm, so it’s worth checking before you buy new bedding or choose a deeper mattress.
Bed height
The combined height of your base, whether that’s a divan or slatted frame, plus your mattress determines how high your bed sits overall. A thicker mattress on a tall base can make getting in and out feel less comfortable, while a thinner mattress on a lower base can leave the bed feeling a little low. It’s worth thinking about the overall height, not just the mattress on its own.
Quality indicator
A deeper mattress often means more substantial comfort layers, whether that’s additional filling above the spring unit or deeper foam layers. It’s not a perfect measure of quality, as densely packed fillings can sometimes be shallower than lighter ones, but as a general guide, mattresses under 20cm are less likely to have a meaningful comfort layer above the springs.
Depth range What it typically indicates Fitted sheet needed
15–20cm Entry level or rolled mattresses with lighter comfort layers Standard sheets (around 25cm depth)
20–25cm Mid range mattresses with a reasonable comfort layer above the support core Standard to deep sheets (25–30cm)
25–30cm Premium designs with more substantial natural or foam comfort layers Deep sheets (30–35cm)
30cm+ Luxury mattresses with thicker comfort layers, often using natural fillings and more detailed construction Extra deep sheets (35cm+)

What is a European king size mattress?

This is one of the most common mistakes people make when buying a mattress, and it’s worth getting clear on before you order.

A European king size mattress measures 160cm × 200cm, which makes it 10cm wider than a standard UK king size while keeping the same length. It’s the size used by IKEA bed frames and many other European bed manufacturers, so it tends to come up more often than people expect.

IKEA bed frames and European sizes
If you have an IKEA bed frame, or any bed from a European manufacturer, you will usually need a European king size mattress (160 × 200cm) rather than a standard UK king size (150 × 200cm).

A UK king size mattress will leave a visible gap of around 10cm within the frame. It won’t just look off, it can also affect how the mattress sits over time and create a less even sleeping surface.

It’s always worth checking the internal dimensions of your bed frame before ordering, especially if you’re mixing UK and European products.
Type Width Length When you need it
UK king size 150cm 200cm Standard UK bed frames
European king size 160cm 200cm IKEA and European manufactured bed frames
US king size (Eastern) 193cm 203cm Imported US bed frames, uncommon in the UK

If you’re not completely sure which size your bed frame needs, the simplest way to check is to measure the internal sleeping platform rather than the outer frame. That measurement will tell you exactly which mattress size to go for.

At Land of Beds, we stock both UK and European king size mattresses across all constructions and tensions, so you’ve got plenty of choice either way. And if you’re unsure, just give us a call on 01928 242829. It’s something we help customers with every day.

A zip and link king size mattress is made up of two separate mattresses, each measuring 75cm × 200cm, joined together to create a full king size sleeping surface. Once connected, it looks and feels like a single mattress, but each side can be a completely different tension.

For couples with different support needs, it’s one of the most practical options available. One person can choose a firmer feel for back support, while the other can opt for something softer to relieve pressure at the hips and shoulders, without either having to compromise.

There’s also a flexibility to it that standard king size mattresses don’t offer. Each side can be unzipped and used separately if needed, and when it comes to replacing the mattress, you can update one side at a time rather than replacing the whole thing.

What bedding size do you need for a king size mattress?

Item Standard UK king size dimensions Notes
Fitted sheet 150 × 200cm, depth typically 25–40cm Check the depth rating matches your mattress and any topper. Deep pocket sheets are usually needed for mattresses over 28cm.
Flat sheet Typically 240 × 260cm Designed to tuck under the mattress on all sides with a comfortable amount of overhang.
Duvet / quilt Typically 225 × 220cm or 230 × 220cm The extra width is intentional and gives both sleepers enough coverage. It is usually best not to size down.
Pillowcases Standard 50 × 75cm or Oxford with border The same as other UK sizes. Pillow size is not affected by mattress size.
Mattress protector 150 × 200cm, depth 25–40cm Should match your mattress depth and sits directly on the mattress under the fitted sheet.
Mattress topper 150 × 200cm Sits on top of the mattress under the fitted sheet. Remember to include topper depth when choosing fitted sheets.
European king size bedding
If you have a European king size mattress (160 × 200cm), you’ll need bedding designed to match. Standard UK king size fitted sheets are usually too narrow, which is something that can easily be missed when ordering.

It’s also worth knowing that European bedding ranges can be more limited and often slightly more expensive, so it’s something to factor in when deciding which size is right for you.

Is a king size mattress right for your bedroom?

Does your room have space?
It’s always worth measuring your room before anything else. A king size mattress works best in a space of around 3.5m × 3.5m, which gives you enough room to move comfortably on all sides. If your room is smaller, a well-made double can often be the better choice, especially if it means you avoid squeezing a larger bed into a space that doesn’t quite support it.
Are you sharing with a partner?
If you are, a king size is usually the point where things start to feel noticeably more comfortable. The space per person increases from around 67.5cm on a double to 75cm on a king size, which is often the difference between regularly noticing movement and sleeping more undisturbed. It’s one of the upgrades people tend to feel straight away.
Are you taller than 5ft 11in?
A king size mattress gives you 200cm in length, compared to 190cm for a standard double. That extra 10cm makes a real difference for taller sleepers. As a general guide, adding around 20cm to your height helps you find the right mattress length, so anyone around 5ft 9in or taller will benefit from the extra space.
Do you co-sleep with children or pets?
In this situation, a king size is often the minimum worth considering. Two adults and a child in a double can quickly feel crowded, while a king size gives you a bit more breathing room. If co-sleeping is something you do regularly, a super king is usually the more comfortable long-term option.

King size mattress FAQs

What size is a UK king size mattress?
A standard UK king size mattress measures 150cm wide by 200cm long (5ft by 6ft 6in). That makes it 15cm wider and 10cm longer than a standard UK double mattress. Each person gets around 75cm of personal space.
Is a king size the same as a super king?
No, they are different sizes. A UK king size is 150cm wide, while a super king is 180cm wide. Both are 200cm long. That extra 30cm gives each person around 90cm of space instead of 75cm, which can feel noticeably more generous. It is a meaningful upgrade, but it also requires a larger room, usually around 4m by 4m, and comes with higher costs for both the bed frame and bedding.
Will a UK king size fit an IKEA bed frame?
No, not usually. IKEA bed frames are made to European king size dimensions, which are 160cm wide rather than 150cm. A UK king size mattress will be too narrow and will leave a visible gap. For an IKEA frame, you will need a European king size mattress measuring 160 × 200cm.
What room size do I need for a king size bed?
As a general guide, a king size bed works best in a room of around 3.5m by 3.5m. This allows for comfortable clearance around the bed, particularly on the sides you use most often. If your room is smaller, it is worth measuring carefully and checking that doors, wardrobes, and walkways still function properly once the bed is in place.
What’s the difference between a UK king and a US king?
A US king size, sometimes called an Eastern King, measures 193cm by 203cm. That makes it wider and slightly longer than a UK king size. They are completely different sizes, so mattresses and bedding are not interchangeable. If you have a US bed frame, you will need to buy a US-sized mattress and bedding to match.
How deep should a king size mattress be?
There is no single ideal depth, as it depends on the type and quality of the mattress. As a general guide, mattresses under 20cm tend to be more basic, while 25 to 30cm usually offers a more comfortable, mid to premium feel. Depths over 30cm are often found in higher-end mattresses with more substantial comfort layers. It is always worth checking that your fitted sheets are suitable for the depth, especially if you are using a topper as well.
Can I use a king size mattress on a double bed frame?
No, it is not recommended. A king size mattress is both wider and longer than a double frame, so it will overhang the edges. This does not just affect how it looks, it also means the mattress is not properly supported, which can lead to uneven wear over time. It is always best to match your mattress size exactly to your bed frame.
Alice Littler avatar

Written by Alice Littler

Alice brings a background in marketing, design, and branding to Land of Beds, where she focuses on making sleep advice simple, relatable, and practical for everyday life. She holds a degree in Graphic Design with a specialism in branding and design, giving her a strong understanding of how interior spaces, colour, layout, and environment can influence comfort, mood, and overall wellbeing. 

Her creative background allows her to provide both expert bed and mattress guidance and bedroom design inspiration that helps customers create spaces that feel as good as they look.

Alongside her work in marketing and branding, Alice has collaborated with internationally recognised brands including Campari and Aperol, Paulaner, and Malfy, helping develop her expertise in consumer-focused communication and lifestyle content. She has also been trained by and works closely with leading UK bed and mattress manufacturers including Harrison Spinks, Hypnos, and Vispring, building extensive knowledge of mattress technology, sleep ergonomics, bedroom comfort, and sleep wellness.

Passionate about the life-changing impact of quality sleep, Alice creates content designed to help readers make informed decisions to improve their sleep environment, wellbeing, and everyday routine.

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Judith brings her background in psychology, neuroscience, and education to her role at Land of Beds, where she shares expert advice to help customers sleep better. From product buying guides to bedtime routines and sleep-friendly habits, Judith’s insights support Land of Beds’ mission to improve sleep for everyone.