At The Sleep Guy, we know that buying a mattress is one of the biggest sleep investments you’ll make. That’s why we carry out a series of rigorous, hands-on tests on dozens of mattresses each year. You can find these individual reviews in our ‘best mattresses’ section.

Here’s a full breakdown of our process, so you can see exactly how we evaluate performance, durability and value.

1. Firmness & Spine Support

We begin with what we call the “spine test”: lying on your back or front and placing a hand between our spine and the mattress surface. You can do this test for yourself when you are mattress shopping.

If your hand fits easily under you back then the mattress may be too firm. If it’s very hard to get your hand in then the mattress may be too soft.

We then move onto our front and side to see how the mattress feels in different sleeping positions.

We record this and convert it into a firmness rating (1 = very soft, 10 = very firm). Firmness is somewhat subjective, but this gives you an indication of sleep posture and suitability. If you can test a mattress for yourself, or get one with a good returns policy then that is ideal!

2. Edge Strength & Support

Next we assess how the mattress holds up at the edges. A mattress that collapses or lacks support can lead to sagging or worn-out edges over time. In our tests we rate edge support and note any soft spots.

We start by lying across the mattress near the edge and seeing how it feels when we lay on our side. Does it feel like we might fall off (not ideal!)? Or does it feel exactly the same as the centre of the mattress (definitely ideal!).

When then sit on the edge of the mattress as if we are tying our shoelaces. We call this the ‘Custard Slice’ test as some mattresses behave in the same way as a custard slice when you bite into it.

3. Motion Transfer & Partner Disturbance

If you’re sharing a bed with someone else then you need to be concerned about motion transfer!

We work in a team of two.

One person lies down whilst the other shuffles around and gets in and out of bed. The person lying down then gives feedback of how much movement they could feel.

Spring-based mattresses tend to transfer more motion; foams tend to do better – but there is some real world variation.

Some others do more complicated tests, such as seeing if certain objects will fall over but we find that a recreation of how you will actually use a mattress is the most useful test.

4. Build Quality, Specification & Features

Next, we dive into the construction details.

What’s the mattress made from? Does the price tag match the specification? Does it have features such as ‘hand side stitching’ that improve durability and strength at the edges? Is it single-sided or double-sided?

Our favourite detail to focus in on is the handles of the mattress. We think that these provide a window into the overall quality and build of a mattress. A strong set of handles with good stitching suggests that a similar high quality construction method will be applied throughout the parts of the mattress you can’t see. It’s also the case that heavyweight and solidly built mattresses need stronger handles to enable you to move them.

5. Warranty and trial period

Next, we dig into the warranty and trial period.

The headlines are often impressive but the small print can sometimes reveal a little more – so we think it’s worth reading!

Some trial periods are more generous than others and will give you a refund and free returns if you don’t like a mattress.

Others will only give you a swap for another mattress and will charge you to return it.

Warranties also need a little investigation. We dig into the detail of whether you are covered for less as time goes on. We also ask how long the company offering the warranty has been trading for. Some mattress brands offer very long warranties, but that won’t be worth anything if these cease trading next week!

6. User feedback and ratings

Where available, we also include review scores for the brand and for the individual mattresses.

These can give a really valuable insight, as it highlights common issues that a lot of people experience. Have lots of people complained about the returns process? Have lots of people found the mattress too hot?

We take these with a pinch of salt though, as there are lots of fake reviews online – both positive and negative!

Final thoughts

Our testing methodology is designed to give you transparent, rigorous, real-world guidance.

Have you tested every mattress on the market?

No, and I’d be amazed if anyone has. The last estimate I read was that there are about 8000 different mattresses available in the UK. However, we have tested dozens of mattresses. Some recommendations are made because we have tested other mattresses manufactured by the same brand and with a similar specification.