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What Size Mattress & Bed Do I Need?

You probably already knew that the firmness or softness of your mattress can affect the quality of your sleep, but did you realise that the size of your mattress can be just as crucial? Sleeping on a mattress that is too small, large, thin, or thick for your body type will mean you aren’t getting enough space or support throughout the night — and that can lead to insomnia, back problems, and a lot of tossing and turning.

The ideal mattress and bed for you depends on things like your height, weight, lifestyle and sleeping environment, so you’ll need to weigh up all your options very carefully before you make a decision. To help you find the optimum size for you, we’ve out together this handy guide to bed and mattress sizes, so you can make sure you get it right first time. We’ll cover:

Mattress Size Guide

What are the different mattress sizes?

Mattress sizes can vary between different countries, and certain sizes can also vary by a centimetre or two depending on the manufacturer. The dimensions of Dormeo mattresses are as follows:

Mattress type


Best for…


90cm x 190cm / 3’ x 6’3’’

This is the usual choice for single sleepers and children, especially in small bedrooms.

Small double or UK queen

120cm x 190cm / 4’ x 6’3’’

Slightly narrower than a standard double, a small double or UK queen mattress allows a generous amount of space for single sleepers, and is also a great fit for small guest bedrooms. It may also suit couples who are short on space.


135cm x 190cm / 4’6’’ x 6’3’’

A standard double mattress will comfortably sleep two people.


150cm x 200cm /

5' x 6'6"


A king bed is longer and wider than a standard double. It’s perfect for taller or heavier people, and couples looking for a bit more room to stretch out.

European king

160cm x 200cm / 5’3’’ x 6’6’’

A European king size mattress is 10cm wider than a standard UK king size. This type of mattress will suit bed frames made in mainland Europe.

Super king

180cm x 200cm

6’ x 6’6’’

This luxurious extra-large mattress is perfect for heavier or very tall couples, or those who really appreciate having their own space.

How do I know which mattress size is right for me?

The right mattress size for you is dependent a whole host of different factors, including your height, weight, whether you sleep with a partner, and the size of your bedroom. Here, we’ve listed everything you need to consider, to help you get an idea of the different options and pick the right mattress for you.

What’s your body type?

The first thing you should consider is your body type. Your mattress needs to be long and wide enough to accommodate you comfortably, or you won’t be able to stretch out and relax during the night. For example, single mattresses are ideal for most single sleepers or children, but they’re not suitable for very tall or heavy people, who will need extra room. Those over six feet tall will benefit from a king mattress, which allows the sleeper an extra ten centimetres to stretch out — perfect if you often find your feet hang over the edge the bed.

How deep your mattress needs to be is largely dependent on your weight. Heavier sleepers will need a deeper mattress — ideally between 25cm to 30cm — as this will help to provide much better support. If there are two of you in the bed, remember that you’ll need to consider how much you both weigh when combined when deciding how deep your mattress should be.

Do you sleep with a partner?

Sharing a bed with a partner can be cosy and intimate, but it can also create a number of problems — especially if your mattress isn’t large enough to comfortably accommodate both of you. If you often find yourself jostling with your beloved for an extra inch or two of space, or you wish you could stretch out a bit more, then it’s a sign that you need to upgrade to a bigger mattress. If you’ve got the room, we would always recommend that you opt for a king or super-king size bed: this will ensure everyone has the space they need to fully relax.

For most co-sleepers, the movements of their partner during the night can be very disruptive, particularly if they’re an active sleeper. It can be very helpful to get a mattress that won’t disturb your partner — a memory foam mattress is perfect for this, as the smart foam material doesn’t allow movement to travel across the mattress. If you haven’t got the space for a king mattress in your room, then a memory foam mattress is a must, as it will isolate your movements and help you to sleep without disturbing one another.

If you don’t sleep with a partner, then a very wide mattress isn’t going to be necessary unless you’re very tall and need the extra length of a king style: a double (or small double, depending on the size of your bedroom) is probably a better idea.

What Mattress Size Do I Need?

Are you an active sleeper?

Do you often wake up in the morning and find you’ve moved over to the other side of the bed, or even shifted your pillows or duvet during the night? If so, then you’re probably an active sleeper. This means that you’re prone to moving around a lot during your sleep. It’s no big deal, but it does mean that you’ll need to make sure your mattress is spacious enough to contain your movements — especially if your nocturnal restlessness is disturbing an unlucky partner on the other side of the bed!

How big is your bedroom?

In an ideal world, we would all have enough room for a super king bed, but we have to work with the space that we’ve got. So, when choosing a mattress, you’ll need to be realistic about what you can actually fit into your bedroom. If you’re struggling to fit a bed which is large enough to comfortably accommodate you, you might want to consider if there’s any furniture which you could move to another room to free up space. After all, your bed is by far the most important item of furniture in your bedroom, so it’s best to prioritise this over less essential items.

Ideally, you should have at least a foot of space on either side of your mattress, to give you plenty of room when getting into and out of bed — this will also make it easier to change the sheets. If you have a very small bedroom and this isn’t possible, then it might be best to focus on the quality of your mattress, rather than the size: this will help you to be comfortable even if you don’t have as much room as you might like.

When deciding on a bed and mattress, you’ll need to remember that the frame on a traditional bed is often a couple of inches larger than specified mattress size. So, you should be careful to check that your bed of choice will fit into your room. If you’re working with a tight space, then it’s a smart idea to opt for a divan bed, as these are often exactly the same dimensions as the mattress.

Now you know everything you need to consider, you’re ready to start shopping for the mattress and bed of your dreams. If you need some extra help before you make a decision, check out our guides and FAQs section for more advice, or get in touch with one of our sleep experts on 0800 625 0134.

Dormeo UK Limited trading as Dormeo, is registered in England and Wales no. 07440398. Registered address: Wye House, 376 London Road, High Wycombe, Buckinghamshire, HP11 1LH. Dormeo UK Limited is Authorised and Regulated by the Financial Conduct Authority as a Consumer Credit Firm under firm number 627302. Klarna Bank AB (publ) is Authorised by the Swedish Financial Services Authority (Finansinspektionen) and is subject to limited regulation by the Financial Conduct Authority. Registered office: Sveavägen 46, 111 34 Stockholm, Sweden. Corporation ID number: 556737-0431.