To help us provide you with free impartial advice, we may earn a commission if you buy through links on our site. Learn more

Best king size mattress 2024: Spacious comfort for couples

Corner of mattress with brass bed frame a

Sleep like a king with the best mattresses from Emma, Simba and more

Struggling to catch forty winks in a bed that’s too small? The best king size mattress can provide you with plenty of room to get a great night’s sleep. If you share a bed with a partner, or you just value your space, a king size mattress can be a welcome upgrade from a double.

With a dizzying array of mattresses available, many of which you can now get rolled up and delivered to your door in a box, trying to find the right mattress for your personal preferences is a task in itself. And if you do sleep with a partner, you’ve got the sleeping habits of two people to take into consideration. It’s enough to make you want to lie down.

However, having tested and reviewed a wide range of mattresses, we promise to bring you the most informed buying advice possible. We’ve put together the following roundup, featuring some of our favourite mattresses to buy in a king size.

Featured deal: Get yourself a free mattress protector worth £99 when bought with a Simba Hybrid Pro mattress

There’s already a lot to like about the five star rated Simba Hybrid Pro mattress, currently priced at £1,329 in a king-size. It comes with a ten-year guarantee, a 200 night trial, and is the recipient of the Expert Reviews Best Buy award. That’s not all though, if you act fast enough you can take advantage of the current deal Simba is offering and bag yourself one of their mattress protectors free of charge when bought with the Simba Hybrid Pro.

Best king size mattress: At a glance

Best memory foam mattress for couplesEmma Original (~£735)Check price at Emma
Best hybrid mattressSimba Hybrid Pro (~£1,749)Check price at Simba
Best for reducing motion transferEve Premium Hybrid (~£1,449)Check price at Eve
Best budget hybridSilentnight Studio Eco (~£509)Check price at Silentnight

How to choose the best king size mattress for you

How big is a king?

A standard king size mattress measures 150cm by 200cm, while a double mattress measures 135 by 190cm. It goes without saying that, if you’re upgrading from a double mattress, you should make sure you have enough space to accommodate a king size.

It’s also worth mentioning that king size mattresses are 10cm longer than singles and doubles, so you might want to invest in a king if you’re especially tall.

READ NEXT: The best mattress toppers to buy

How we test mattresses

It’s probably pretty obvious, but we test our mattresses by sleeping on them. While it might sound somewhat straightforward, there are also a number of key factors we take into account. With the inclusion of comfort and support, we place focus on temperature control and firmness – though with some mattresses we will also consider edge support and motion isolation.

When looking at temperature control, all-foam mattresses will feel warmer than other models, making them less suitable for those susceptible to overheating at night.

We also consider the base on which you put your mattress – whether it be a hard divan base, sprung slatted bed or even the floor – it will affect how the mattress feels beneath you. And though we can’t always test a selection of bed bases when reviewing a mattress, we will always consider this in our final decision.

Following our initial tests, we consider any trial runs that might be available – which is often the case with the bed-in-a-box market – before asking the all-important question, is the product good value for money?

Regardless of whether you’re after a single, double or king size, we recommend checking out our dedicated mattress buying guide, as well as some of the other pages listed below:


The best king size mattresses you can buy in 2024

1. Emma Original: Best memory foam mattress for couples

Price when reviewed: £735 | Check price at EmmaUPDATE: Since publishing our review, Expert Reviews has noticed a recent influx of negative customer reviews for Emma Sleep on Trustpilot, with many customers complaining of delays to shipping and a lack of communication. We’ve been told that the brand is working on resolving these issues, and has updated the updated delivery times on its website. We will be sure to bring you more information as we receive it.


The Emma Original is our top pick for couples thanks to its versatility: the brand’s all-foam mattress is exceedingly comfortable to sleep on in a range of positions. So if you’re a side sleeper while your partner prefers to sleep on their back, you don’t need to worry about finding a compromise.

Admittedly, the Emma Original does feel quite soft compared to some of its bed-in-a-box rivals and, because it’s an all-foam mattress, it’s perhaps not the best choice for those who get very warm in bed. Nevertheless, the Emma Original offers great levels of comfort and support. It’s well-suited to any sort of bed base (sprung or solid slatted) and doesn’t need to be flipped or rotated. You will also get a 200-night trial with a money-back guarantee if you find that the Emma Original isn’t for you.

Read our full Emma Original review for more details

Key features – Type: Memory foam; Needs turning? No; Sizes: Single to super king (including EU sizes); Warranty: 10-year warranty, 200-night trial with money-back guarantee

Check price at Emma

2. Simba Hybrid Pro: Best hybrid mattress

Price when reviewed: £1,749 | Check price at Simba One of our very favourite hybrids, the Hybrid Pro sits in the middle of Simba’s mattress range (between the regular Hybrid and the Hybrid Luxe). It’s constructed from a combination of foam, two layers of micro pocket springs and an upper comfort layer made from British wool (which also helps you stay cool during the night).

The king size Hybrid Pro costs a fair bit at £1,749. However, it’s worth pointing out that, like most bed-in-a-box mattresses, you get a lengthy trial period (200 nights), at the end of which you can return it for a full refund if you’re not happy with it. Besides, we would argue that a mattress this comfortable and supportive is well worth its price tag.

Read our full Simba Hybrid Pro review for more details

Key features – Type: Wool, foam and micro pocket spring hybrid; Needs turning? Rotate once/month for the first six months; once every 3/6 months thereafter; Sizes: Single to king; Warranty: 10-year warranty, 200-night trial with money-back guarantee


3. Silentnight Studio Eco: Best budget hybrid

Price when reviewed: £509 | Check price at Silentnight If you’re after something more affordable (after all, not everyone has the budget to splash out over £1,000 on a new mattress), then the Silentnight Studio Eco is a decent choice.

As well as being cool and comfortable, you can also make the case for the Studio Eco hybrid mattress that it’s more environmentally friendly compared to memory foam models. Instead of using polyurethane plastic which is the key ingredient in memory foam, it’s made from recycled synthetic fibres alongside a layer of full-size pocket springs.

The main downsides are the lack of edge support and a disappointing trial period (a 60-night comfort exchange), but the Studio Eco is a sensible budget choice nonetheless.

Read our full Silentnight Studio Eco review for more details

Key features – Type: Recycled synthetic materials and pocket springs; Needs turning? Rotate once/month for the first few months; Sizes: Single to king; Warranty: 5-year warranty, with 60-night comfort exchange trial

Check price at Silentnight


4. Eve Premium Hybrid: Best for reducing motion transfer

Price when reviewed: £1,299 | Check price at Eve

Of Eve’s extensive mattress range (the bed-in-a-box brand has no fewer than six foam and hybrid mattresses), we found the Premium Hybrid to be the best. Like the Emma Original, it’s a great choice for couples, largely thanks to its ability to reduce motion transfer. This means that you can sleep soundly even when your partner is tossing and turning during the night.

Beyond this, the Premium Hybrid strikes an excellent balance between comfort and support. Eve also recently extended its mattress trial period from 100 nights to 365 nights, meaning you can try it for a full year and return it for a full refund if it’s not the right one for you.

Read our full Eve Premium Hybrid review for more details

Key features – Type: Foam and pocket spring hybrid; Needs turning: Rotate once every month or so; Sizes: Double to super king; Warranty: 10-year warranty, 365-night trial period with money-back guarantee

Check price at Eve


Read more

Best Buys