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How We Test Mattresses

By Ben Slater

Discover how we test mattresses to find the best mattresses that will support your body in sleep and last for years to come. 

Put us to the test

Our Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.

Trying out a mattress in a shop gives you an idea of how comfy it is, but you need to know whether it will still give you a good night's sleep in years to come. Buy the wrong one and your comfy mattress could turn into a saggy dud. That's where Which? mattress reviews come in.

We test memory-foam and pocket-sprung mattresses more thoroughly than anyone else. We can tell you everything you need to know about each mattress, including the niggling issues that you wouldn't otherwise discover until it was too late. Our tests are based on years of testing experience, and we buy everything we test ourselves. So we're completely independent of any manufacturers and can give you honest unbiased reviews.

Our reviews answer the most crucial questions about mattresses:

  • How well does the mattress support my back?
  • Is the mattress easy to move and turn?
  • Does the mattress move a lot when my partner turns on it?
  • Does the mattress get soggy with sweat?
  • How durable is it?
  • Should I buy it?

Discover which products topped our tests in our mattress reviews.

How well does the mattress support my back?

A good mattress keeps your spine in the same shape as when you’re standing up. To assess each mattress for back support, we measure the shape of a person's body at 36 different points when standing, and then when lying on their back on the mattresses.

We also measure the position of their spine when they're lying on their side, to check that no part of their body sinks too far into the mattress. A good mattress keeps your spine in line and parallel to the mattress.

We use people with different body types for this test to ensure each mattress is suitable for a wide range of people.

Is the mattress easy to move and turn?

Turning a mattress helps it stay in good condition, so our tests take account of how easy a mattress is to flip and move.

A good mattress can be turned by one person without help. Our assessments cover how easy a mattress is to turn, whether it has handles to help with this, and how heavy it is.

Great mattresses aren't so rigid that they're hard to turn, but also aren't so bouncy that they bend and slip around when you pick them up.

Does the mattress move a lot when my partner turns on it?

A mattress that jiggles each time your partner moves in the night can disturb your sleep, so we measure whether you feel the mattress moving when a sleeping partner turns on it. 

A good mattress will be stable enough that it won't disturb your sleep.

Does this mattress get soggy with sweat?

We test the mattress to see how it deals with moisture. We rate mattresses higher when they allow sweat to escape from the mattress so that it stays dry.

How durable is it?

In our tests, heavy barrels are run back and forth across each mattress thousands of times, to simulate approximately 10 years of use. We then examine whether the mattress gets harder or softer over time, and whether the mattress starts to sag or gets damaged in any other way. 

Good mattresses will stay in a similar condition to when you first bought them, even after heavy use.

70%The score a mattress needs to earn in our tests to be a Which? Best Buy

Should I buy it?

Each of the assessments described above contributes to making up a total test score, which is the overall percentage figure awarded to each mattress.

But certain assessments are more important than others and so carry different weights. The Which? test score ignores the price of a mattress and is based on:

  • 55% performance (including how well it supports your body)
  • 40% durability
  • 5% ease of use

A mattress needs to score 70% or above to be a Best Buy. Those scoring 40% or below are rated as Don't Buys - these are mattresses that are so bad we think you should avoid them altogether.

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