stacked pillows on bed

The Ultimate Bed Size Guide

Author: James Higgins

There are many reasons you might be on the lookout for a new bed and mattress: you may have moved into a new home, decided your current solution has seen better days, or hoping to complement a renovated bedroom style. But choosing a size that comfortably suits your space may turn out to be more complicated than you first anticipate.

In this article, we’ve explained the differences between the various UK bed sizes (single, double, king, super king, and emperor), including dimensions and suitability, as well as how to make sure you’re choosing the right size bedding, the reasons you might want to consider a larger mattress, and how to determine what size bed is best for your room.

What are the different bed size dimensions?

In the UK, there are several sizes of bed to choose from, with each offering its own benefits depending on your requirements. To give you an idea of the different dimensions, before going into detail for each, we’ve compared the five sizes you can buy pillows, duvets, and mattress protectors for here at Ethical Bedding. 




3'0" x 6'3"


4'6" x 6'3"


5'0" x 6'6"

Super king

6'0" x 6'6"


6'6" x 6'6"


Looking at each side-by-side, you’ll notice that the length of each bed remains roughly the same, with doubles and singles only marginally shorter than king size, super king size, and emperor mattresses (although, of course, this makes all the difference if you’re particularly tall!) Instead, the increasing width as you go up sizes is where the difference between each is most-significant.

How Big is a Single Bed?

As the name suggests, single beds and single mattresses are suitable for solo sleepers, and, measuring a cosy 3’0” x 6’3”, are ideal if you only have a small bedroom or limited space. 

While adults can generally sleep comfortably in a single bed, many lean towards larger sizes for increased comfort and space to spread out. However, if you’re buying bedding for the family, single mattresses are large enough to accommodate growing children, from toddlers all the way through to teens – meaning you’ll not need to buy a new frame for many years.

How Big is a Double Bed?

When buying new bedding, you’d perhaps be forgiven for assuming a double mattress is twice the size of a single. But, in fact, the double bed size is only roughly 1.5 times as wide, and exactly the same length. 

However, that doesn’t mean doubles aren’t big enough for two adults to sleep comfortably together. In fact, double bed frames are the most common in the UK, which also makes double mattresses among the most popular sizes.

How Big is a King Bed?

With king size bed dimensions coming in at 5’0” x 6’6”, they’re noticeably larger than the aforementioned double. And with the additional size often comes improved comfort and sleeping space, ideal for couples who love to have a bit more room to themselves at night, or those that occasionally invite the cat or dog into bed!

Before buying a king size bed, though, be wary of its size and how much space it’ll take up in your bedroom. As a rule of thumb, you might want to avoid picking a king size bed unless you have a room measuring at least 12’ x 12’, to avoid feeling cramped. If space is tight, we recommend you consider scaling down a little and perhaps choosing a double bed instead. 

How Big is a Super King Bed?

A foot wider than a standard king size bed, dimensions of a super king bed come in at a whopping 6’0” x 6’6”, offering more than enough room for couples to comfortably spread out and enjoy their own space. Perfect for large bedrooms, super kings are a serious centrepiece; however, if you want extra room for yet-additional indulgence, consider sizing up once more and picking out a striking emperor bed. 

How Big is an Emperor Size Bed?

So, what size is an emperor bed? Coming in at an impressive 6’6” x 6’6”, emperor beds offer an abundance of space for couples who love to spread out and enjoy a peaceful night’s sleep with room to get comfortable. While many UK retailers don’t cater to such a size, we believe a regal emperor mattress should be complemented by soft and breathable duvets, sheets, and pillows. 

Before buying an emperor bed, however, due to their size, it’s especially important to accurately measure your bedroom dimensions.

Emperor Size Bed vs Super King: Choosing the right bedding

If you’re opting for one of the bigger bed sizes, such as an emperor or super king, it’s important to ensure you choose the right bedding for optimal comfort and convenience. Made with strong elastic, our high-quality sheets and duvets are designed to fit snugly over your mattress, so you never have to worry about peeling sheets or cold toes again! 

How to choose the right size bedding

We’ve compared emperor and super king duvet covers and bed sheets with king size and double beds, to give you an idea of the dimensions needed for each type of mattress. 


Size Duvet & Duvet Cover

Fitted Sheet

Flat Sheet Mattress Topper & Protector


140 x 200cm

55 x 79"

90 x 190 x 34cm

35 x 75 x 13"

180 x 275cm

78 x 108"

90 x 190 34cm

35 x 75 x 13"


200 x 200cm

79 x 79"

140 x 190 x 34cm

55 x 75 x 13"

230 x 275cm

91 x 108"

140 x 190cm

55 x 75"


225 x 220cm

89 x 87"

150 x 200 x 34cm

59 x 79 x 13"

275 x 275cm

108 x 108"

150 x 200cm

59 x 79"

Super King

260 x 220cm

102 x 87"

180 x 200 x 34cm

71 x 79 x 13"

305 x 275cm

120 x 108"

180 x 200cm

71 x 79"


290 x 235cm

114 x 87"

200 x 200 x 34cm

79 x 79 x 13"

320 x 290cm

126 x 114"

200 x 200cm

79 x 79"

How to choose the right size pillows

Just as your sheets and duvet are important in ensuring a comfortable night’s sleep, so are your pillows. To give you an idea of the type of pillows you’ll need, we’ve compared regular pillowcases and large square pillowcases with those that suit a super king size bed.


Size Pillow Pillowcase Pillow Protector


(Included with all Fitted Sheet and Duvet Cover sets)

 50 x 75cm

20 x 30"

50 x 75cm

20 x 30"

50 x 75cm

20 x 30"

Super King

(Not included in bedding sets)

50 x 90cm

20 x 36"

50 x 90cm

20 x 36"

50 x 90cm

20 x 36"


(Not included in bedding sets)

65 x 65cm

26 x 26"

65 x 65cm

26 x 26"

65 x 65cm

26 x 26"


Our pillowcases are easy to slip on and off.
No more pillow wrestling on laundry days - unless you like that sort of thing!

Is a bigger bed better?

We’ve compared the different types of bed found in the UK, but is it always better to choose a more formidable frame and mattress? We’ve picked out a few reasons why you might want to buy a bigger bed. 

1. Enjoy more personal space 

It might sound obvious, but the bigger your bed, the more personal room you have to spread out and enjoy. For example, if you’re sleeping on your own, a double bed can be much more comfortable than a single, and, for couples, king size, super king size, and emperors are perfect if you’re both prone to sprawling!

This comes with plenty of benefits, not least reducing the number of times you’re woken up or disturbed by a wriggling or fidgeting partner. With a larger bed, you can always sleep close together, with the luxury of also being able to enjoy your own space.

2. Bigger frames can be great value for money

A bigger bed might cost a bit more than a smaller alternative in the short term, but, over the course of its lifetime, it’ll likely be a negligible difference – potentially a matter of pennies per week if you keep the same frame for many years. With this in mind, it can be well-worth investing in a more comfortably-sized bed, that provides you with extra space to enjoy a more relaxing night’s sleep.

3. We spend a third of our lives in bed

When choosing a bed, it’s important to remember just how much of your life you’re going to spend there – around a third of the time, in fact! As such, it’s important to pick out a frame and mattress that makes the time spent in bed as comfortable as possible, to best-reenergise you for the hours that you’re awake. 


How to determine what size bed is best for you

When choosing a new bed, it’s important carefully consider which size is best-suited to your space. A bed that’s too big can make your room look a bit odd, while a small bed in a large room can sometimes feel lost and out of place.

Generally, around 30-35% of your bedroom should be taken up by your bed, which, for an emperor size bed, means a bedroom measuring around 18’ x 18’ - which is a terrific size. Other things to consider when determining what size bed is best include:

  • Walking space - you’ll want a reasonable walking space around your bed, with your frame ideally at least 70-80cm away from the nearest wall, window, or piece of furniture.
  • Plug sockets - check where the plug sockets are in your bedroom before buying your bed. You don’t want to buy a frame that’s too large before realising it covers your power banks and charging ports. 
  • Practicality – a practical point to bear in mind when buying a bed is whether you’ll actually be able to fit your chosen frame up your stairs and through your doors, let alone in your bedroom. A lot of beds allow you to self-assemble, but it’s well-worth confirming before you buy.

Why choose Ethical Bedding?

No matter the size of bed you choose, it’s important to ensure you’re complementing it with comfortable and quality bedding. Each Ethical Bedding duvet, sheet, and pillow offers warmth, cosiness, and luxurious softness, guaranteeing you an excellent night’s sleep.

But that’s not all; as a wholly sustainable company, we’re committed to bringing you completely carbon neutral bedding – letting you sleep better at night knowing you’re having a positive impact on the environment. Our eucalyptus silk is responsibly resourced, using 95% less water than would be used if we collected cotton, while we also donate a portion of all sales to sustainability initiatives around the world. 

Explore our complete collection of bedding bundles, suitable for all mattress sizes ranging from single to emperor, or check out even more from our team of passional experts over on our blog