Your Sleep Matters!

How Do I Choose The Right Mattress Size?


Nicky P.

Last updated: 26.02.2021 6.5 Min.

Even if buying a mattress can be a real headache, choosing its composition, size, and firmness are necessary steps. After all, humans spend a third of their life sleeping.

Choosing the right mattress, then, is of vital importance.

But choosing the size of your mattress is just as important to ensure a comfortable and restful sleep. There are many different mattress sizes available. But which size is right for you?

Use our mattress size guide to help you make the right choice.

Mattress Size
  • Overview
  • What mattress size is best for you?
  • Available sizes
  • Choosing the right mattress size
  • FAQ
  • Conclusion
  • Our selection of the best mattresses

What mattress size is best for you?

This is can seem like an impossible question to answer. Indeed, choosing the right mattress size will depend very much on a number of unique personal attributes, including your body weight, height, and the size of your bedroom.

Some guiding questions you may ask include the following:

  • Are you and your partner tall, average height, or short?
  • Do you sleep alone or do you share your bed with another person?
  • Do your children or your pets often sleep in your bed?
  • Are you or your partner restless sleepers and often get in each other's way?
  • Is your bedroom big enough for a wide mattress?

Which mattress sizes are available?

There are dozens of different mattress sizes available, including standard sizes and custom sizes. Not only that, but each country will also have different standard sizes. In the UK, for example, the standard sizes are different to those available in mainland Europe. This means that the dimensions of a Double Bed, for example, will be different in the UK than it would be in Germany. That said, many standard European sizes are also available in the UK, and which sizes are available will depend entirely on the manufacturer.

But you’ll also find mattresses with lengths of 210 cm or 220 cm, generally referred to as oversized mattresses. You’ll also occasionally find unusual dimensions or custom sizes.

Not every manufacturer will offer custom sizes or oversized mattresses. If you or your partner are very tall (over 2 metres), then an oversized or extra-length mattress is highly recommended. You wouldn’t want your feet sticking out in winter!

Below you'll find the guide on the most common UK mattress sizes and who they are most suitable for.

Mattress Sizes

Mattresses sized 90 x 190 cm (3’ x 6’3” - UK Single)

The 90 x 190 cm and 90 x 200 cm mattresses are some of the most common sizes. These are well-suited for singles but two mattresses can also easily be combined to form a double bed. To connect the two mattresses and make sleeping more comfortable, it’s simple to add a bed bridge. The best thing about this mattress size is that you can store it easily - it simply doesn’t take up much space! Both UK and EU sizes are commonly available in the UK, though some manufacturers will only offer the UK sizes.


Mattresses sized 135 x 190 cm (4’6” x 6’3” - UK Double)

The 135 x 190 cm and 140 x 200 cm mattresses are some of the most popular mattresses available. The Sleep Hero Team has tested countless of these mattresses, giving you accurate reviews based on real experience. We would recommend this mattress size for singles wanting a bit more space as well as couples with limited space. Singles with pets will also find this mattress quite comfortable. Both UK and EU sizes are commonly available in the UK, though some manufacturers will only offer the UK sizes.


Mattresses sized 150 x 200 cm (5’ x 6’6” - UK King)

A king-size mattress is good for couples. If placed on a double bed, this one mattress can provide sufficient space for two people. Singles who like a lot of space will also enjoy this size.


Mattresses sized 180 x 200 cm (6’ x 6’6” - Super King)

A 180 x 200 cm mattress is the ideal size for couples. It can be placed on double beds or box spring beds. On a mattress of this size, you can choose to cuddle with your partner but also take up your own space without restricting your partner or worrying that you will disturb your partner’s sleep.


Mattresses sized 200 x 200 cm (6’6” x 6’6” - Emporer)

The Sleep Hero team has reviewed numerous mattresses of this size and can suggest the very best ones. This mattress size is suitable for couples, offers a lot of space, and can also be used by three people (mother, father, and child).


Child mattresses

The 90 x 190 cm or 90 x 200 cm are popular child mattress sizes. There are also smaller sizes available that are suitable for babies or toddlers. We’ve taken a closer look at the best mattresses for children and have summarised what you should look out for when buying.


Choosing the right mattress size

The "right" mattress size depends on your needs and requirements. Here are a few suggestions.

For couples

Most couples choose mattresses sized 150 x 200 cm or 180 x 200 cm. With mattresses of these sizes, most couples will have enough room for a comfortable and restless sleep without getting in the way of their partner. If your partner likes to lie crosswise or moves quite frequently while sleeping, then a slightly larger mattress would be better. In this case, we would recommend a minimum size of 180 x 200 cm.

Do you prefer to cuddle while sleeping? Then a 135 x 200 cm or 150 x 200 cm mattress can also be a good option. Bedrooms often aren’t big enough to accommodate wider mattresses.

What if your child or your dog likes to hop into your bed at night? Then you should definitely choose a wider model such as the 180 x 200 cm or 200 x 200 cm.

And if you or your partner are larger or taller people? Then you should consider buying a longer mattress. As a rule of thumb, the mattress you choose should be at least 20 cm longer than your height. For example, if you or your partner is 190 cm tall, then your mattress should be at least 210 cm long.

For singles

Most singles will choose a mattress of at least 90 x 190 cm. But this mattress is too narrow to allow for two people sleeping on it. As far as space permits, we would advise singles to choose a mattress size of 135 x 190 cm or 150 x 200 cm. These are suitable for singles and couples. If your bedroom isn’t very large, then you can also get away with a mattress size of 90 x 190 cm.

Adolescents and children can also rest comfortably on smaller sizes, such as the 90 x 190 cm mattresses. Both of these are good options if the bedroom isn’t large enough to accommodate a wider mattress. Before you buy a new mattress, you should always measure what size mattress would fit into your room.

If you’re slightly taller, then you should consider an extra-long mattress, such as 210 cm or 220 cm. There is nothing worse than having your feet dangle over the edge of your bed.

For children and babies

Mattresses for children and babies are considerably smaller at 60 x 120 cm or 70 x 140 cm. These are designed for small children. The 90 x 190 cm mattresses are popular with older children as it offers more space.

Children sleep longer than adults and they also tend to be more restless. A good children’s mattress should be able to allow for this. It’s also important to pay attention to how children’s mattresses are made. You wouldn’t want a mattress that contains harmful substances. Of course, this is also something to consider when you purchase a mattress for yourself.

We’ve summarised what to pay attention to when buying a mattress for your child in our article on the best children’s mattresses.

Baby Mattress

Frequently asked questions

We answer your most frequently asked questions.

What is the best mattress size?

There is no "best" size, only the best for you. Consider the size of your bedroom, the space you have around your bed, the furniture in your bedroom, and how much space you need while sleeping.

What is the best size for couples?

Most couples choose a 150 x 200 cm king bed. If there are no bedroom space constraints, then the 180 x 200 cm size is most common.

How thick should my mattress be?

The thickness of the mattress depends on its composition. If you buy a foam, memory foam, or latex mattress, we would recommend a mattress with a minimum thickness of 18 cm. For spring mattresses, we would recommend a minimum thickness of 23 cm.

Can you place two mattresses next to each other?

In the past, it was common practice to place two smaller mattresses next to each to form a double bed. This is highly recommendable for partners with a weight difference of 15kg or more or if you're choosing pure spring mattresses, which tend to have bad motion transfer.

Choosing two smaller mattresses has the advantage that each partner can choose a mattress that's right for them, with their desired level of firmness. The only problem with placing two mattresses next to each other is the gap that remains between them. This can easily be solved by adding a bed bridge.


There are many different mattress sizes available - and you can easily find the one best for you! We always recommend standardised sizes as these allow you to find bed frames, box springs, and bed linen that will fit your mattress perfectly. That said, a standard size may not be right for you and if you are still having problems choosing a mattress to suit your body, then you can also order a custom-sized mattress.

Our selection of the best mattresses

Looking for a new mattress to help you get the best night's sleep? Here are our top recommendations.

Additional information

Nicky P.

My mum calls me "bear" because I like to sleep so much. I never knew that, one day, that would be a very useful skill. Can you tell that I've found my calling? 

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