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15 November 2021

Best mattresses 2021: Which? Best Buys and expert buying advice

We reveal our pick of the best mattresses available to buy, based on the results of our impartial rigorous lab tests
Lisa Galliers
A pocket sprung mattress

If you want a good night’s sleep, deciding which type of mattress to buy is only part of the story. 

Whether you prefer a pocket sprung or memory foam mattress, our tests have found big differences between the best and worst of each mattress type.

Make the wrong choice and you risk being lumbered with a needlessly expensive mattress that's uncomfortable, unsupportive and unable to stand the test of time without sagging and softening. 

With the quality of your sleep and the support of your spine at stake, do you really want to risk spending a fortune on an unsupportive mattress that won't stand the test of time?

Well, fortunately you don't have to. Our independent and rigorous lab tests have uncovered the best mattresses. We've got Best Buys starting from £129, so a good night's sleep might cost less than you expect.

All of our Best Buy mattresses performed well in our tough body-support and durability tests. 

Best premium mattress

Only logged in Which? members can view our recommendations in the tables below. If you're not yet a member, join Which? today.

  • 81%

    This pocket sprung and memory foam hybrid is one of the best mattress money can buy. It provides good support whatever position you sleep in; it’s excellent at preventing the transfer of movement from one side of the bed to the other; and you can sleep safe in the knowledge that it will stand the test of time without sagging, softening or becoming less supportive.

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Best cheap mattress

  • 74%

    It's rare that we test a poor mattress from this brand, and this one doesn't disappoint. It's supportive for both larger and smaller people when new and it doesn't sag, soften or become less supportive over time. It's also suitable for restless sleepers, as it's very easy to roll over on. Doing so may disturb a light-sleeping partner, however, as it isn't the best at preventing the transfer of movement from one side of the bed to the other.

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See our best cheap mattress recommendations.

Best memory foam mattress

  • 77%

    This simple memory foam mattress is affordable and a great Best Buy option if you usually sleep on your front or your back. It has a 7.5cm foam core and another 10cm layer of viscos foam on top. This top layer of memory foam will envelope your body, while this will help stop the transfer of movement across the bed (great news for your bed fellow) it does make it harder to turn over on.

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See our best memory foam mattress recommendations.

Best pocket sprung mattress

  • 77%

    We first tested this mattress in 2015, and it was one of the best we had seen in years. Several years on, we’re still yet to test a pocket sprung mattress that can match this Best Buy. This mattress contains several layers of foam, which may not be to everyone’s liking, but you’re in luck if you like the feel of it in the shop. You can sleep well in the knowledge that this mattress will support your spine for years to come without sagging or softening. It’s also a good bet for both restless and light sleepers because, while it’s very easy to turn on, it also does a great job at absorbing bounces.

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See our best pocket sprung mattress recommendations.

Best boxed mattress

  • 81%

    This impressive mattress aced our tough tests. It's supportive, stable, breathable and long-lasting. It's one of our highest-scoring mattresses from this bed-in-a-box brand.

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See our best boxed mattress recommendations.

All tables updated November 2021.

View all mattress reviews to compare our lab-tested recommendations. 

The worst mattresses to avoid

Even if you find these mattresses fantastically comfortable when you try them in the shop, we would advise against adding them to your short list. Comfort doesn't guarantee support or durability, and all three mattresses have serious flaws in at least one of these areas.

  • 44%

    Despite coming from a well-respected brand, you'll want to think twice before buying this mattress. It provides poor support for people sleeping on their back and, over time, the support for back-sleepers becomes even worse while the mattress also sags dramatically.

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  • 46%

    Despite decent support in most positions when new, this is a poorly-scoring mattress, mainly because it’s very bad at preventing the transfer of movement and it sags significantly over time. It's worth avoiding.

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  • 49%

    This low-scoring mattress has been around for a number of years. While it did well in some parts of our testing, it sags severely and support deteriorates over time. It's particularly bad for back sleepers. The flaws in its durability make it hard to recommend.

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View our Don't Buy mattresses.

Video: how to buy the best mattress

Watch our video to help you pick the perfect mattress for your sleeping position, body shape and bedroom.

Mattress firmness explained 

Contrary to popular belief, a mattress doesn’t have to be hard to be good for you. Firmness comes down to personal preference, as long as it does a good job of supporting your body.

Time and again, our mattress tests have shown you don't have to buy a firm mattress to get excellent and long-lasting support.

Don't assume that what's classed as a firm mattress will feel the same in different shops. Firmness is subjective, and manufacturers describe the firmness of their mattresses in a range of ways. 

That's why we don't use terms such as soft and firm in our reviews. Instead, we test mattress firmness on a scale of one to 10, where one is the firmest and 10 the softest, so you can easily compare the firmness of different mattresses. 

We also measure how supportive each mattress is for a range of different body sizes and sleeping positions, so whether you prefer to sleep on your front, side or back, we've got you covered. 

Medical-sounding terms, such as ‘orthopedic’ and ‘posturepedic’, don't necessarily mean a mattress is better for you. There are no restrictions on the term 'orthopedic mattress', so any mattress can use that description. 

The body-support rating we give in our mattress reviews shows how well each mattress keeps your spine in its natural position. This is your best guide to finding one that's good for your back.

Use our mattress reviews to arm yourself with a shortlist of supportive mattresses to try in store.

Uncomfortable mattress

Types of mattress

There are four main mattress types to choose from: pocket sprung, latex, coil and memory foam. Mattresses of all types have impressed in our tough tests, so the type you choose really comes down to personal preference and how much you want to spend.

Most mattress manufacturers make more than one type, and the manufacturing process and cost will be different for each. 

Price isn't everything, though – the most important thing is what you, as an individual, find comfortable.

The most common type is a coil mattress, which can be either open coil or continuous coil. 

Not sure which type of mattress is best for you? We look at the pros and cons of the main types to help you find out.

Pocket sprung mattresses

The insides of a pocket-sprung mattress

If you want a traditional mattress with a natural filling, such as wool, you'll want a pocket sprung mattress.  

Pros of pocket sprung mattresses

  • Each spring is enclosed in its own fabric 'pocket' – and each reacts to pressure from your body independently

Cons of pocket sprung mattresses

  • Can be expensive
  • Our tests show that some can sag significantly over time
  • Don't mould to your shape in the same way as memory foam
  • They're generally not as warm as memory foam mattresses, which could be an important consideration if you tend to find yourself too hot at night

Mattresses with spring systems are usually padded with synthetic polymers, but some contain natural fibres such as horsehair or wool. These layers can affect firmness and breathability, both of which we test in every mattress. But more layers aren’t always better – the support from the springs is more important.

With springs, it's quality rather than quantity that's important. We've tested mattresses with densities ranging from 440 to 1,085 springs, and found wide variation in the level of support offered.

We've tested some great pocket sprung mattresses at a range of prices, so you're sure to find one that suits you. Go to our best pocket sprung mattresses or our full list of pocket sprung mattress reviews see which ones we recommend.

Memory foam mattresses

The insides of a memory-foam mattress

Memory foam mattresses, also known as memory mattresses, are topped with a layer of temperature-sensitive viscoelastic material (memory foam). 

This makes the shape of the mattress change to fit the shape of your body, and also tends to make the mattress feel warmer. 

Pros of memory foam

  • Moulds to your body shape
  • More durable

Cons of memory foam

  • Can be expensive
  • Can restrict movement
  • Can increase body temperature

You'll find everything you need to know about this increasingly popular type of mattress in our guide to the best memory foam mattresses

If you already know you want a memory foam mattress, you can find the right model for your budget and body type by comparing our full list of memory foam mattress reviews or memory foam and springs mattress reviews.

Continuous coil and open coil spring mattresses 

The insides of an open-coil mattress

Continuous coil mattresses are made from a single looped wire and open coil mattresses are made of single springs fixed together by one wire. 

Pros of coil mattresses

  • Cheaper than other types of bed mattress

Cons of coil mattresses

  • If you share a bed, you're more likely to be disturbed by your partner moving around during the night because the springs move as one unit (we call this 'stability' in our tests)
  • The coils in these mattresses wear out more quickly than pocket springs, so you’re likely to end up rolling together eventually 

When we surveyed Which? members to find out more about mattresses, those who own an open coil mattress are less likely to say it helps them to get a good night's sleep than those who own other types. 

You can find out more about our survey results, in our mattress brand reviews. Or, head straight to our open coil mattresses reviews.

Latex mattresses 

Latex is a less common type of mattress which has a core made up of layers of springy latex. 

Pros of latex mattresses

  • Manufacturers claim that they're more resilient and better able to keep their shape

Cons of latex mattresses

  • Tend to be expensive

Manufacturer Dunlopillo specialises in latex beds, although the Dunlopillo mattresses we've reviewed don't come cheap. 

Mattress toppers

These are different from mattress protectors in that they add a layer of extra padding to your existing bed. Mattress toppers can be made of memory foam or other materials. 

However, they can be as expensive as buying a new mattress in some cases, and won’t provide more support if your old mattress is already sagging. 

Discover which are the best mattress topper brands according to our survey of more than 1,000 mattress-topper owners.

Should I buy a bed-in-a-box mattress? 

These are mattresses that you buy online, and they come vacuum-packed into a box and delivered direct to your door. There are four reasons why you should consider one: 

  • By cutting out the retailer and selling direct from manufacturer to consumer, many brands claim you’re getting a higher-quality mattress for less. 
  • Most online-only mattresses come with a sleep trial of at least 10 weeks. During this time you can try the mattress at home and send it back for a full refund if you don’t like it. In most cases, the manufacturer will collect the unwanted mattress from your house free of charge before recycling it or donating it to charity. 
  • Bed-in-a-box mattresses can be available in all types – mainly foam, or memory foam, but now we're also seeing more hybrid mattresses (combining foam and springs) from these brands.
  • We’re yet to test a bad one. More than half of the Best Buy mattresses we've uncovered can only be bought in a box. See our list of the top five bed-in-a-box mattresses. 

See our guide to the best bed-in-a-box mattress including a look at online brands Casper, Emma and Eve.

Should I buy a rolled-up mattress?

Hot on the heels of the bed-in-the-box craze, the rolled-up mattress is gaining popularity. These mattresses come vacuum-packed in a handy cotton bag, so you can take them home with you. Alternatively, they can be delivered to your home and easily taken to the room you need – without having to try to wrestle a large mattress up your stairs or around tight corners.  

However, they sometimes need to be aired or left for a fair few hours to regain shape, which might be a faff if you need to use it quickly. 

Best mattress features to look out for

Memory foam mattress

As mattresses serve a single basic function – to help us sleep – they don't come overloaded with jazzy features. But there are still a few things to look out for.

One-sided mattress

As the name suggests, only one side of a one-sided mattress is designed to be slept on. 

Mattresses can be extremely heavy – the heaviest we've seen weighs more than 50kg – so you might be relieved that you don't need to flip it. 

You'll probably still need to rotate it from head to toe, though, so it's a good idea to check the ease-of-use rating in our mattress reviews. 

Natural fillings

Many pocket sprung mattresses also contain layers of synthetic fillings, such as foam. 

If you're keen to avoid these, look out for mattresses that are specifically claimed to be made using only natural materials. 

Look carefully at the claims, though, some might only have a token layer of natural materials. 

Memory foam

Similarly, just because a mattress contains memory foam, it doesn't make it a memory foam mattress. 

We only class a mattress as memory foam if it contains more than just a token layer of the body-moulding material. See all our memory foam mattress reviews. 

What are the best mattress brands? 

Find out what people think of the brand of mattress they own in our guide to best and worst mattress brands. Our survey results cover major brands such as Casper, Ikea, John Lewis, Sealy and Silentnight.

How much does a good mattress cost?

A new mattress can cost anywhere between £100 and several thousand. 

Factors such as brand, size and the types of material used can all have a significant impact on cost. But, as the graph below shows, our mattress tests have found that you don’t need to spend a fortune to get a mattress that will support your spine and last for years. 

Number of Best Buy mattresses by price

PriceNumber of Best Buys
Less than £3005
More than £9003

See our list of the best cheap mattresses and the best mattress deals

Try your mattress before you buy, if you can

Buying a mattress online might be cheaper and more convenient but, unless you’re buying a bed-in-a-box mattress, it’s always best to try before you buy if you possibly can - and if shops are open.  

When we asked Which? members about their experience of buying a mattress, more than a third told us they feel intimidated trying out a mattress in the shop. 

A good mattress shop shouldn't mind you doing this. See our guide on the best mattress shops

When trying out a mattress in store: 

  • wear comfortable clothing and remove your outdoor gear
  • lie on a mattress for at least 10 minutes, in positions you normally sleep in
  • go with your partner if you share a bed
  • don’t shop for beds when you’re tired, as all the mattresses will feel great
  • don't let sales assistants influence you – they can’t decide whether the mattress is comfortable for you. 

If you’re buying a memory foam mattress, relax in one position, then move into another. Was it easy or did you struggle to move? If you struggled, you might find that the memory mattress restricts your movement too much, especially in cold weather when the foam will be harder. 

Make sure your mattress fits your bed base

Manufacturers may encourage you to buy a mattress and bed base together, and this is a good idea if you’ve had your old base for many years. 

If you buy the mattress and base separately, or are going to keep your old base, measure carefully to make sure they’re a good fit. Dimensions can vary, so don’t rely on a new double mattress being exactly the same size as your old one. 

For more information, read our guide what bed size do you need? 

Buying a mattress online?

If you’re looking for a bargain mattress, one option is to try a few in a shop, before going home to search for the best price online. 

That’s what 6% of Which? members did when they bought their last mattress, according to our recent October 2020 quick poll.  

Unsurprisingly, given the events of 2020, around 76% responded to say they'd bought online (without trying their mattress first). 

Meanwhile, 16% tried a mattress in store before having it delivered to their house.

If you can't get to the shops at the moment, here are our top tips for buying online:


When you buy online you’re protected by consumer law. But do your research first: read our reviews and opt for a model that best fits your sleeping style. We have picks for front, side and back-sleepers, people who fidget a lot, and those that tend to get too hot or cold. 

Use trial nights offers 

Find out whether your chosen mattress has a trial period, how long this lasts and how you return it once the trial is up. Look for any hidden costs involved, and whether you have to return the mattress back in the original packaging or not. 

Check the guarantee/warranty on your mattress

Make sure you know what your rights are if there's a problem with your mattress. Most guarantees for mattresses won't cover gradual wear and tear, which leads to loss of support. 

You should also check whether there’s anything in particular, such as removing labels or using a base other than a recommended one, that would invalidate the guarantee. 

Know your rights when buying a mattress

If you change your mind, you’re entitled to a 14-day cooling-off period from the date you receive goods. This means you can cancel your order at any time from the moment you place your order up to 14 days from the date it arrives, and the seller is obliged to refund you. Find out your rights to returns and refunds

Now you know what to look for, check our mattress reviews for a Best Buy that will support your spine and last for years.

How we independently test mattresses

Not only does no one else test mattresses like us, but we’re also totally independent, so you can have complete confidence in our results.

If you tend to sleep on your back, a good mattress will keep your spine in the same shape as when you’re standing. So, we measure the shape of a person's body at 36 different points when standing, and then again when lying on their back on the mattresses, to see how well they compare. 

If you’re a side-sleeper, your spine should be parallel to the mattress, so we use a laser to measure the angle of a person's spine relative to the bed. 

Are you a front sleeper? We also measure the spine a third time to assess how supportive each mattress is for people who prefer to lie on their front.

After simulating several years of use by rolling a heavy barrel over the mattress thousands of times, we then repeat the body-support tests to see whether the mattress becomes less supportive over time.

That’s not all. With our results, you can see how breathable a mattress is, how easy it is for you to turn over on and how stable it is. If you’re a light sleeper, you should try to buy a mattress with five stars for stability. These are the best at absorbing bounces, so you’ll be less likely to be disturbed when your partner rolls over or gets up in the night.