Best king size mattresses
Every spring count in UK mattress marketing refers to a king size, which makes this the one size where the numbers mean what they say.
I earn a commission if you buy through some links on this page. It never changes what I recommend, and I publish negative verdicts on brands I earn from. Editorial independence.
A UK king is 150 by 200 centimetres, and it is the size the industry quotes everything in.
That matters more than it sounds. A mattress advertised with 3,000 springs has 3,000 in a king. A double has fewer and a single fewer still, because spring density stays roughly constant while the area shrinks. So comparisons between brands only hold at this size.
For two people, a king gives 75 centimetres each. That is better than a double's 67.5 and short of the 90 centimetres a super king provides, which is the width of a single bed.
It is also ten centimetres longer than a double, which matters if either of you is tall.
The picks
The pick, if you want one answer
Origin LumbarCloud Mattress, 8.2 / 10. Thirty-five centimetres and up to 8,000 springs, which is more of both than mattresses at twice the price.
| Product | Best for | From | Score |
|---|---|---|---|
| Origin LumbarCloud Mattress | Best overall | £797 | 8.2 / 10 |
| Origin Hybrid Pro Mattress | Best value | £374 | 8.4 / 10 |
| Otty Original Hybrid Mattress | Best if you sleep hot | Around £500 | 8.1 / 10 |
| Mlily Supreme 10000 | Best for disturbed sleep | Upper mid | 6.9 / 10 |
| Tweak | Best if you disagree on firmness | Mid range | 7.8 / 10 |
Origin LumbarCloud Mattress: Best overall
£797 · 8.2 / 10
Thirty-five centimetres and up to 8,000 springs, against Simba's Hybrid Ultra at 34cm and 7,300 for £1,749 and Brook + Wilde's Ultima at 30cm and around 6,000 for £1,395. Deeper and more heavily sprung than either, at well under half the price.
Buy it if
You are of average or heavier build and want maximum structure per pound.
Do not buy it if
You are under about eleven stone. The lower third does little for you.
Read the full Origin LumbarCloud Mattress review
Origin Hybrid Pro Mattress: Best value
£374 · 8.4 / 10
The highest scoring mattress on this site at 8.4. Most people buying a king do not need 35 centimetres, and this is the point where a mattress is simply good rather than specialised.
Buy it if
You want the strongest general specification without spending much.
Do not buy it if
You are heavier and want maximum depth.
Read the full Origin Hybrid Pro Mattress review
Otty Original Hybrid Mattress: Best if you sleep hot
Around £500 · 8.1 / 10
Scores 8.1. A 16 centimetre spring core, which is a support structure rather than a thin comfort layer of springs. Worth separating from the usual comparison: Simba's Aerocoils are 25mm and sit above a foam base. Both are sold as hybrids and they are not the same thing.
Buy it if
Heat is your main complaint and you want structure rather than treatment.
Do not buy it if
You want to sink in.
Read the full Otty Original Hybrid Mattress review
Mlily Supreme 10000: Best for disturbed sleep
Upper mid · 6.9 / 10
Ten thousand springs in a king is roughly one every 1.7 centimetres, which earns the only 10 out of 10 for motion isolation on this site. Units that small must use thin wire, so it is unambiguously plush rather than supportive.
Buy it if
One of you wakes the other and neither of you needs firm support.
Do not buy it if
Either of you is heavier. This is a plush specification.
Read the full Mlily Supreme 10000 review
Tweak: Best if you disagree on firmness
Mid range · 7.8 / 10
Scores 7.8. A different firmness on each side. Every dual firmness mattress has a transition zone down the middle, and at 75 centimetres each a king works reasonably, though a super king at 90 works better.
Buy it if
You and your partner differ in weight or preferred firmness.
Do not buy it if
You both want the same thing.
Spring counts, and how to read them in other sizes
| You are | Aim for | Why |
|---|---|---|
| Under 11 stone | 1,000 to 2,000 | You do not load the springs enough for grouping to matter |
| 11 to 16 stone, firm | 1,500 to 2,500 | You barely compress the surface, so fine gradation does little |
| 11 to 16 stone, plush | 3,000 and up | You sink, so each region must respond independently |
| Over 16 stone | 1,500 to 2,500, firm, 30cm deep | Stronger springs, not more of them |
| Disturbed by a partner | 4,000 and up | Motion isolation is what high counts genuinely excel at |
The fourth row runs against how the category is sold. Above about 2,000 springs in a king, counts rise by using thinner gauge wire in smaller units: you gain contouring and motion isolation, you lose individual spring strength, which is exactly what a heavier body depends on.
King against the sizes either side
| Size | Dimensions | Each of two |
|---|---|---|
| Double | 135 x 190cm | 67.5cm |
| King | 150 x 200cm | 75cm |
| Super king | 180 x 200cm | 90cm, the same as a UK single |
A European king is 160 by 200, which is neither a UK king nor a super king. It will not take UK fitted sheets and it will not fit a UK frame, which catches people buying imported bedding and furniture.
Three practical checks before ordering
The route in. Measure doorways, stair turns and landing width, not just the bedroom. A sprung mattress bent around a tight turn can have its spring unit permanently damaged, and that voids most guarantees. A boxed mattress solves it.
The base. Slats no more than about 7.5 centimetres apart, and a centre rail with at least one supporting leg. At 150 centimetres wide the middle carries the most load and is furthest from any support.
Sheet depth. Modern hybrids run 28 to 35 centimetres and standard UK sheets are cut for around 25. Budget for deep fitted sheets or you will be straightening corners for years.
And buy the duvet a size up
A king duvet on a king bed leaves nothing hanging over the sides, so it slides off with movement and lets warm air out at the edges. Two people pulling in opposite directions consume the overhang first.
A super king duvet on a king bed is the usual recommendation. If you and your partner disagree about warmth, two single duvets is better still: tog is per duvet rather than per person, so any shared number is wrong for one of you every night.
What not to do
Compare spring counts across different sizes. Every count you read is a king.
Buy a very high spring count for support. Five thousand springs is a plush specification.
Order before measuring the route in.
Use a king frame without a centre leg.
Buy a European king expecting a UK king. A European king is 160 by 200 and takes neither UK sheets nor a UK frame.
Also considered, and why they are not here
A roundup is only as useful as what it leaves out, so here is what was assessed and rejected for this list.
| Product | Why it is not on the list |
|---|---|
| Simba Hybrid Ultra | Thirty-four centimetres and 7,300 springs at £1,749, which Origin beats on both counts for well under half. Refurbished units have listed at around £699. |
| Brook + Wilde Ultima | Thirty centimetres and around 6,000 springs at £1,395. The original company was liquidated in 2023 and relaunched, which matters on a long guarantee. |
| Simba Hybrid Essential | Scores 5.2, the lowest mattress score here. At £549 it exists to make the model above it look reasonable. |
| Nectar Premier Hybrid | The 365 night trial is the longest in the UK mainstream and the best reason to buy it. On construction alone others give more per pound. |
How this list is made, and who made it
Independence
No brand pays to appear on this site and no placement is sold. Some links earn a commission if you buy, which never changes a score, an order or a verdict. Several of the lowest scores here are on products that carry commission, and several recommendations carry none.
Who writes this. Kyle Klinkradt has worked in the mattress and bedding industry for over ten years across retail, distribution and brand partnerships, and has handled, sold or assessed products from every major UK bed-in-a-box brand. Every review on this site is written by one person, so the scores mean the same thing from page to page.
What the assessment is. Construction specifications against what they physically do: spring height and where in the mattress it sits, spring count for the size, gauge, whether the base is sprung or foam, foam density where it is published, comfort layer depth and material. Then the commercial terms that decide what you are actually buying: trial against returns policy, guarantee length against the company's UK trading history at Companies House, and the regulatory record.
What it is not. This is not a laboratory. I do not publish pressure-mapping data or claim to have slept eight years on every mattress here, because nobody has and pages that imply otherwise are not telling you the truth. Where a judgement rests on construction rather than long-term use, the review says so.
What gets a product removed. Leaving the UK market, a specification change that makes the review inaccurate, or a corrected fact. Brands that have withdrawn are kept on the site with the score removed rather than quietly deleted, because people still search for them.
See editorial independence, corrections and the author page.
How these were chosen
Every product here has its own review on this site with a score out of 10, and the score is a judgement rather than an average. Nothing appears in a list because it pays more.
A score is against the market, not against its own range. The cheapest mattress in a lineup is usually priced to make the model above it look reasonable, and the flagship of a budget range has risen into a bracket where better brands compete. Both are judged against what else you could buy for the money.
Everything listed can actually be bought in the UK. That is not a given: Casper withdrew in July 2020 and Leesa no longer sells here, and both still appear in current British roundups with affiliate links attached.
I do not pad the list. Where only three or four products genuinely qualify, there are three or four. A list of seven when the category contains four good ones is a list with three bad recommendations in it.
Prices move constantly. Judge the cash price on the day rather than any percentage beside it. See every review on this site or where the real savings are.
Questions people ask
How big is a UK king size mattress?
One hundred and fifty by 200 centimetres, giving each of two people 75cm. That is better than a double's 67.5cm and less than a super king's 90cm, which is the width of a UK single.
Do advertised spring counts refer to a king size?
Yes. Spring density stays roughly constant while the area shrinks, so a double has fewer and a single fewer still. Comparisons between brands only hold at king size.
How many springs should a king mattress have?
Between 1,500 and 2,500 for firm support at most weights, and 3,000 or more if you want a plush surface. Above about 2,000, counts rise by using thinner wire, which buys contouring at the cost of individual spring strength.
Is a European king the same as a UK king?
No. A European king is 160 by 200 centimetres, which is neither a UK king at 150 nor a super king at 180. It will not take UK fitted sheets or fit a UK frame.