How to find a good firm mattress for back pain among Amazon's Prime Day deals — 5 tips from an expert bed tester

Amazon’s 10th annual Prime Day sale event starts on July 16th, with 48 hours of discounts across a huge range of products - including mattresses. More and more mainstream mattress manufacturers are selling their beds via the retail giant, so we're expecting to see some significant savings. But can you find a decent firm mattress in the Amazon Prime Day deals? Yes. And as a mattress tester, I’m going to show you how.

We've tested the year's best mattresses and many of our top bed choices come with luxuriously firm support. But before you add to card, you need to be sure that a firm bed is actually the best choice for your body type and sleeping position.

Some deals for Amazon Prime Day 2024 are already live, with some of them listed at the end of this guide. But you’re likely to see even better deals and more choice next week, so it pays to know what you are looking for in advance. Here are my top tips to  finding the right firm mattress for you.

What is a firm mattress and are they best for back pain?

A firm mattress, sometimes referred to as a hard mattress, rates at between 8 and 10 out of 10 on the firmness scale. The best firm mattresses provide a firmer surface to sleep on, where you’ll lie on top of the mattress rather than sinking in. That’s not to say that there won’t be any contouring and you should feel as if you’re floating on the mattress, rather than lying on a stiff and unyielding plank. Most firm mattresses are hybrids, made from a combination of coils and foams as the coils provide more support.

As someone who suffers from lower back pain, I’ve often found that firm mattresses offer the right amount of support for my lumbar region, as well as preventing any unwanted pressure from being transferred to the hips and shoulders. Sciatica sufferers (a condition that affects the lower back, hips and legs) also often report improvement from sleeping on a firm mattress. But it’s important to note that firmness is subjective – as a lightweight sleeper I know that I find a mattress rated at 8/10 firmer than someone of a heavier build would.

It's important to note that firm mattresses are the right option for all back pain sufferers. If you suffer with upper back pain, you might find that a medium firm mattress is a better fit. This is because it will provide a little more softness at the pressure points of the shoulders and will help them to sink in enough to provide cushioning and pressure relief.

How to find a good firm mattress for back pain on Amazon

With an ocean of mattresses to choose from on Amazon, how do you find the right firm mattress for you? These are the key points to consider:

1. Check that it’s suitable for your sleep position

Firmness is subjective and not everyone fits neatly into a designated box. But your sleeping position will play a big part in the type of mattress you should choose, regardless of whether you're shopping for the best cheap mattress or the best cheap Amazon mattress. In general, stomach sleepers will benefit hugely from a firm mattress, as it will keep their hips lifted and spines aligned.

Back sleepers could also benefit from a firm mattress but should take care to check that the natural ‘S’ curve of their spine isn’t being flattened out. Lastly, it’s likely that many side sleepers will find a firm mattress too hard, not allowing for enough sinkage and contouring around the shoulders and hips. If you sleep predominantly on your side, you may want to consider a softer mattress.

2. Does it have excellent lumbar support?

You may have heard the term but might be wondering what lumbar support is . The lumbar region is part of your spine and refers to the five vertebrae in your lower back. It spans from your ribcage to your pelvis and is one of the most common places for people to experience back pain (referred to as lower back pain).

A mattress with excellent lumbar support will maintain the natural ‘S’ curve of your spine, which curves inward at your lower back. Superior lumbar support means that the mattress will fill the gap between your lower back and the sleep surface, without forcing the spine’s curve to be flattened out.

What should you look for on Amazon? Choose a mattress with enhanced lumbar support, which often consists of a strip running down the mattress to support the lumbar region. Reinforced coils and zoned support are also features to look out for.

3. Look for a mattress with a depth of at least 11”

Amazon marketplace is home to hundreds and hundreds of mattress, which can make it difficult to spot the best Amazon mattress for your sleep needs. Bed depth is important and the best firm mattresses will be at least 11" tall (the only exception to this is the Purple Original, which has a depth of 9.5" and is incredibly supportive). But generally, a deeper mattress allows for more structure and layers, which allows brands to add in more support for a firmer mattress.

A thicker support core allows for better stability, and it will also help the mattress to last longer and prevent sagging. Do remember that you also need to consider the depth of your bed base, as you don’t want to make the combination so thick that you can’t get into bed comfortably.

4. Is it supportive enough for your weight?

As well as finding a mattress that suits your sleeping style, you need to also find the right one for your body weight. One of the plus sides of firm mattresses is that they’ll also be incredibly supportive for heavier bodies, with some of the best mattresses for heavy bodies rating high on the firmness scale. Light and average weight back sleepers may also find a firm mattress comfortable but could find it doesn’t offer quite enough contouring for adequate pressure relief. And, whilst heavier side sleepers will enjoy a firm mattress, it’s likely that light and average weight sleepers will need a softer feel.

5. Ensure it comes with a sleep trial, warranty and returns period

If you buy a mattress online direct from the brand it will come with all of the above. But before you leap at a good deal on Amazon, do check that the mattress you want still comes with these perks.

Being able to test a mattress at home is vital – it’s a rare mattress that feels 100% ‘right’ from the first second you sleep on it. It takes times for our bodies to adjust to a new mattress and you need time to decide if it’s the right fit for you. This is also why a returns policy is so important – even if there’s no trial period, you’ll want to be able to return it for a full refund. Lastly, a warranty is important in case there are any faults or issues with the mattress down the line.

3 early Prime Day firm mattress deals

1. DreamCloud Hybrid Mattress: from $419 at Amazon
The DreamCloud is our top Amazon mattress choice, thanks to its blend of firm support, luxurious finishes and sheer value for money. During our DreamCloud mattress review , our lead tester rated it at 8/10 for firmness, but with a surprising amount of cushioning around the pressure points of the shoulders and hips. Right now, a queen is $665 on Amazon, which is the same price as the brand’s website, but we may well see a bigger discount for Prime Day. View Deal

2. Tempur-Pedic ProAdapt Mattress: from $2,149 at Amazon
Yes, Tempur-Pedic mattresses are expensive, but the quality is second to none. While many Tempur mattresses are soft and have a lot of sinkage, the ProAdapt comes in a firm finish to offer more support for a wider variety of sleepers. Amazon currently have a queen listed for $2,949 whereas you’ll pay $3,399 on the brand’s website, so this is a sizeable saving. View Deal

3. Purple Original mattress: From $999 at Amazon
With Amazon Prime Day fast approaching, we're hoping to see some surprise savings on the Purple Original, which is one of our highly recommended beds for back pain sufferers. Right now a queen is $1,499 at full MSRP - but that price could be about to come down. Be warned - although you'll get a 10 year warranty buy buying directly from Purple, it's unclear if Amazon will honour any warranty periods or sleep trials. View Deal