Mattress Sizes UK: The Complete Size Chart in cm and Feet

There are seven standard UK mattress sizes: small single (75 × 190cm), single (90 × 190cm), small double (120 × 190cm), double (135 × 190cm), king (150 × 200cm), super king (180 × 200cm) and emperor (200 × 200cm). Those figures come straight from the size guides published by Which? and Expert Reviews, which agree to the centimetre, and Tempur’s UK size guide lists the same numbers. Width always comes first in British sizing, so “135 × 190” means 135cm across and 190cm from head to foot.

If you only remember one thing, remember this: the three smallest sizes, plus the double, are all 190cm long, and only the king and above step up to 200cm. That 10cm is the quiet reason so many tall Brits are uncomfortable on a double. It also means a UK mattress size is defined by two numbers, not one, and you need both to match your frame.

A note on the feet column. British bed sizes are still sold in imperial — a “4ft6” is a double, a “5ft” is a king, a “6ft” is a super king — but the conversions are rounded. A 150cm king is really 4ft 11in, and a 135cm double is closer to 4ft 5in. Nobody manufactures to the imperial figure any more, so when a listing gives both, trust the centimetres.

A note on tolerances, too. Mattresses are not machined parts, and a sprung or foam mattress can come in a centimetre or so either side of its nominal size. That is normal, and a standard bed frame allows for it. What it can’t absorb is a mattress built to a different standard altogether — which is exactly what happens when a European or IKEA-size mattress meets a British frame. We cover that trap in its own section below, because it is the single most expensive sizing mistake UK buyers make.

Tables are precise, but they are bad at showing how much bigger one bed feels than another. The drawing below puts every UK size on the same scale. Look at the jump from small double to double — just 15cm — and then from king to super king, a full 30cm. Those are the two decisions most British shoppers agonise over, and the drawing makes the answer fairly obvious: the first step is small, the second is big.

Two other things jump out. First, the emperor is a square: 200 × 200cm, as long as it is wide. Second, the single, small double and double look stubby next to the king and above. That shorter length matters more than most people expect. Someone who is six foot tall (183cm) has just 7cm to spare on a 190cm mattress before their feet hang off, and that is before you account for a pillow. On a 200cm king, the same person has 17cm.

If you’d like the American picture — twin, full, queen, California king and so on — our US mattress sizes guide draws all of those to scale too. This page sticks to what you can actually buy in British shops and from UK mattress brands.

A single mattress in the UK is 90 × 190cm, or 3ft × 6ft 3in. It is the most-searched mattress size in the country by a distance, because every child moves into one and most guest rooms have one. When people search for a “mattress for single” bed, this is the size they mean, and it is the size nearly every bed frame labelled “single” in a British shop is built for.

The small single is 75 × 190cm (2ft 6in × 6ft 3in) — 15cm narrower than a single but exactly the same length. It exists for cabin beds, bunk beds, mid-sleepers and box rooms where every centimetre counts. Expert Reviews is blunt that small singles aren’t suitable for most people over the age of seven, and we agree: for anyone past primary school, 75cm leaves no room to turn over without an elbow over the edge.

Here’s the trap with singles. Some bunk beds and cabin beds take a small single, some take a full single, and a few imported frames take a 90 × 200cm “Euro single” that Which? lists separately. A 90cm mattress will not squeeze into a 75cm bunk, and a 190cm mattress will slide around in a 200cm frame. Measure the inside of the frame — not the outside — before you order. Bunk beds are also often designed around a maximum mattress depth so the guard rail stays effective, so check the manufacturer’s instructions on depth as well as width.

Which mattress should go in a single? For a child, a sprung or hybrid mattress usually makes more sense than soft memory foam. Kids bounce, sit on the edge and grow fast, and a sprung core handles that better. On the UK shortlist in our best mattress UK guide, the Silentnight Eco Comfort Pocket 1200 is the obvious single: pocket sprung, made in the UK and priced single £379 · double £499 (silentnight.co.uk, oct 2026). For a teenager or adult on a single, any of the hybrids on that list works; the Panda Hybrid Bamboo single was £649 at full price when Expert Reviews priced it. Our kids’ mattress guide covers what to look for in more depth.

One adult on a single? It’s fine if you are of average build and sleep fairly still. If you are broad-shouldered, a side sleeper who draws up their knees, or simply tall, the 190cm length and 90cm width will feel cramped quickly. That is where the small double earns its place.

A small double mattress is 120 × 190cm, or 4ft × 6ft 3in. You will also see it called a “three-quarter” bed and, confusingly, a “queen” — Which? lists it as “small double (queen-size)” and Expert Reviews titles it the same way. That British “queen” has nothing to do with the much larger American queen, which is 152 × 203cm. If you see “queen” on a UK listing, check the centimetres: it almost always means 120 × 190cm.

For one adult, the small double is the best value bed in Britain. It gives you 30cm more width than a single — a third more room — while fitting into rooms where a double would leave no space to open the wardrobe. It is the bed we’d put in a studio flat, a narrow box room, a teenager’s room once they outgrow a single, or a guest room that also has to work as a study.

For two adults, it is a compromise. Each person gets 60cm, which is narrower than a small single. Which? puts it politely: “Two adults will find a small double mattress pretty snug.” For the occasional weekend guest couple, that is acceptable. For a couple sleeping on it every night, it isn’t — and the same applies, slightly less severely, to the double.

The awkward thing about the small double is price. Because it uses nearly as much material as a double, it costs nearly as much: Expert Reviews listed the Panda Hybrid Bamboo small double at £789 against £799 for the double. A tenner for 15cm of extra width is a bargain, so if your room genuinely fits a double, buy the double. Choose the small double only when the room — or the frame you already own — decides it for you.

Availability is the other catch. Most UK mattress brands sell a small double — Panda and Simba both price one — but bedding ranges are thinner on the ground than for doubles and kings. Before you commit, check you can buy fitted sheets and a mattress protector in 120 × 190cm from your usual shops. You cannot borrow a double’s sheets: a 135cm fitted sheet on a 120cm mattress bunches and slips.

The UK double is 135 × 190cm (4ft 6in × 6ft 3in). The UK king is 150 × 200cm (5ft × 6ft 6in). Which? reports that the king is now the most popular size among its members, with around four in ten owning one, and the double the second most popular. That ranking tells you where the market has gone: a generation ago the double was the default couple’s bed; today it is the king.

The difference is 15cm of width and 10cm of length. That sounds small, but it’s 7.5cm more per person, and the 10cm of extra length is the difference between a six-footer’s feet resting on the mattress or hanging off it. In area, the king is about 17% bigger than the double (30,000cm² against 25,650cm²).

Our verdict: if two adults share and the room can take it, buy a king. At 67.5cm each, a double gives two people less personal width than a small single gives one child. You will notice your partner’s every turn, especially on a bouncy sprung mattress. Upgrading to a king costs surprisingly little: Expert Reviews priced the Panda Hybrid Bamboo king at £889 against £799 for the double, and the Simba Hybrid Pro king at £1,329 against £1,279. For £50 to £90, it is the cheapest comfort upgrade in the whole mattress market.

When is the double still the right choice? When you sleep alone and want space to sprawl. When the room is much under 3m wide, which is where a king starts to leave less than comfortable walking room on both sides (see the room guide below). When you are keeping a well-made double frame and only replacing the mattress. And when both partners are smaller and sleep still. Otherwise, go king.

If you are moving from a double to a king, remember that everything else changes too: frame, headboard, sheets, duvet and protector. That can add up to more than the price difference on the mattress itself. Our best mattress for couples guide covers motion isolation and edge support — the two features that matter most when you share — and the UK picks with the strongest record for couples are the Simba Hybrid Pro and the Nectar UK Memory Foam.

A super king mattress is 180 × 200cm, or 6ft × 6ft 6in. Which? describes it as the size of two standard single mattresses side by side, and that is a useful way to think about it: each sleeper gets 90cm, exactly what they would have in a bed of their own. It is the bed we recommend most often to couples who wake each other up — a restless partner, different bedtimes, a child who arrives at 3am, or a dog that refuses to sleep on the floor.

The super king also has a practical trick. Many brands sell it as a “zip and link” pair: two 90 × 200cm singles that zip together. That makes it easier to get up a narrow staircase, and it means each half can have a different firmness if you and your partner disagree. If you go that route, check the zip line isn’t uncomfortable in the middle, or add a topper across both halves. Check the length of each half, too: if the pair is 200cm long, the halves won’t fit standard 190cm UK single frames later.

The emperor is 200 × 200cm (6ft 6in × 6ft 6in), the biggest standard UK size. Which? calls it easily big enough for two larger-than-average adults, but warns that not many brands make mattresses this big. Expert Reviews also lists a “large emperor” at 214 × 214cm, which is a bespoke size rather than one you will find in most ranges. Among our UK picks, Panda sells an emperor (£1,050 at full price when Expert Reviews checked, though it had sold out at the time). Bedding is the hidden cost: emperor sheets and duvets are specialist items and are priced accordingly.

Should you buy a super king? If the room fits it — roughly 3.3m wide for comfortable access on both sides — and you share the bed, yes. The price step from king is modest: Expert Reviews priced the Panda super king £70 above the king and the Simba £130 above. If you are torn between a super king and an emperor, buy the super king; the extra 20cm rarely justifies the bedding hunt. Our king-size mattress guide is US-focused, but its advice on large-bed edge support and motion isolation applies to UK super kings too.

If you want the short version, here it is. Pick the smallest size that gives each sleeper at least a single’s width and lets a tall sleeper lie flat with space to spare, then check the room can still breathe around it. For most single adults that is a small double or double; for most couples, a king; for couples who disturb each other, a super king.

A few more rules of thumb help with the edge cases. If either sleeper is over about 5ft 10in, skip the 190cm sizes and go king or bigger for the 200cm length. If you have a growing child who might move into the bed, consider whether a single now means a second mattress in three years’ time — a small double often lasts longer. And if one of you runs hot, more width helps more than you would expect: two bodies 90cm apart trap far less heat than two bodies 67cm apart. Our hot sleepers guide covers the materials side of that.

A mattress size is only half of the question. The other half is the room. Expert Reviews suggests leaving at least a foot (about 30cm) on each side to walk round the bed; Which? recommends aiming for 76cm (2ft 6in) between the bed and the nearest wall or furniture. We’ve turned those two figures into a simple room guide: the tight version uses 30cm on both sides and at the foot, the comfortable version uses 76cm.

Read the result as a floor, not a target. Our numbers are for the mattress alone — a bed frame, headboard and footboard can add 10 to 20cm in each direction, and Expert Reviews warns to check the specification of the specific frame. Ottoman and drawer beds need more again, because you need space to lift the base or pull the drawers out.

The practical takeaways. A double works in a room about 2m wide if you accept a squeeze. A king wants roughly 2.1m at a pinch and 3m to feel unhurried. A super king needs 2.4m at the very least and about 3.3m to be pleasant. Many British second bedrooms are narrower than that, which is why the small double remains so common in them. Before upgrading, mark the new bed’s footprint on the floor with masking tape and live with it for a day — open the wardrobe, the drawers and the door. If anything collides, the bigger bed will be a daily irritation, however nice it is to sleep on.

Which? also mentions a design rule of thumb — a ratio of around 1:3 between bed and bedroom “is sometimes said to look best” — while admitting that can be difficult in practice. We’d treat it as a nice-to-have: walking space beats proportion.

This is the section that saves people money. Continental Europe uses a different set of mattress sizes, built on a 200cm length and widths in round 10s: a Euro single is 90 × 200cm, a Euro double 140 × 200cm and a Euro king 160 × 200cm, according to Which?. Compare those to British sizes and you can see the problem straight away. A Euro double is 5cm wider and 10cm longer than a UK double. A Euro king is 10cm wider than a UK king. Only the super king lines up exactly, at 180 × 200cm.

Why does this matter in Britain? Because plenty of UK homes have European-size frames in them — older IKEA beds, frames bought from continental retailers, and furniture brought over from abroad. Archers Sleepcentre, a UK retailer that stocks Euro sizes, says it carries them “to cater for the popularity of IKEA and European size beds in the UK today”. Tempur notes that the 160cm Euro king is often called a “continental double” on larger vintage or continental beds. If you put a standard UK double (135 × 190cm) on a 140 × 200cm frame, it slides around and leaves a gap at the foot. If you try to put a Euro mattress into a UK frame, it simply won’t go in.

IKEA itself has moved towards British sizes in these islands. Its Irish size guide lists standard single, small double, double, king and super king in the familiar UK dimensions and states: “We do not stock European mattress sizes.” But the same guide lists an IKEA “small single” at 80 × 200cm, not the 75 × 190cm British standard, plus a 90 × 200cm “junior”. So even within one retailer, size names don’t travel safely. And if you bought your IKEA bed some years ago, Which? advises checking which size it is — you may have a European double.

How to avoid the mistake: measure the inside of your frame (not the old mattress, which may have compressed) in centimetres, both width and length. If it reads about 140 × 200 or 160 × 200, you need a Euro-size mattress, and most of the big UK online brands don’t make one in their standard ranges — you’ll be shopping from specialists. If it reads 135 × 190 or 150 × 200, buy any UK mattress you like. And bedding follows the mattress: Euro sizes need Euro sheets.

If you read American mattress reviews — including most of ours — the size names will mislead you. Sleep Foundation gives the US standards as twin 38 × 75in (about 97 × 191cm), full 54 × 75in (137 × 191cm), queen 60 × 80in (152 × 203cm) and king 76 × 80in (193 × 203cm). Put those next to British sizes and the names slide one step: a UK king is roughly a US queen, and a UK super king is the nearest thing to a US king, though still about 13cm narrower. A UK double and a US full are within a couple of centimetres of each other.

That has two practical consequences. First, US bedding does not fit UK beds properly — a US king fitted sheet will swim on a UK king, and a US queen sheet is a few centimetres too long. Second, many of the mattresses you see in US reviews — Saatva, DreamCloud, Puffy, Bear — aren’t sold in the UK at all, so there’s no British size to buy. Our UK mattress guide explains which beds you can actually order here, and our US sizes guide has the full American chart, including the California king and the oversized Alaskan king. If you’re in Australia, sizes differ again — see our Australian mattress sizes guide.

Baby beds follow their own standards. In the UK, the usual cot mattress is 60 × 120cm and the usual cot bed mattress is 70 × 140cm, as nursery mattress maker NaturalMat lists them. A cot bed is designed to convert into a toddler bed once the sides come off, which is why it is longer and wider; a 60 × 120cm mattress in a 70 × 140cm cot bed would leave dangerous gaps, so always buy to the exact size of the cot.

Fit matters more here than anywhere else in this guide. The Lullaby Trust’s safer-sleep advice starts from a simple line — “The safest cot is a clear cot” — and a mattress that is the wrong size undermines that, because any gap between mattress and cot side is a gap a baby can wriggle into. Older, second-hand and imported cots don’t always match today’s standard sizes, so measure the inside of the cot and buy a mattress made for exactly that measurement, rather than trusting the name on the box. Our kids’ mattress guide covers what happens next, when your child graduates to a single.

Less than you might think. Mattress prices don’t rise in proportion to area, because a lot of what you pay for — the brand, the delivery, the box, the trial — costs much the same for a single as a super king. Here are the full-price figures Expert Reviews reported for two of our UK picks.

Three patterns stand out. The small double barely saves money over a double — £10 on the Panda — so choose it for the room, never the price. The double-to-king step is cheap — £90 on the Panda and £50 on the Simba — and it is the upgrade we’d make first. And the super king costs only a little more again: £70 more than the king on the Panda, £130 on the Simba. Per square centimetre, bigger beds are clearly better value; the real extra cost of a super king lies in the frame and bedding rather than the mattress.

Two caveats. These are list prices, and UK online brands discount almost constantly — our UK guide notes that Nectar UK is usually 40–45% off and OTTY’s king commonly sells for around £660 against a £1,200 RRP (Expert Reviews’ 2024 full price). And price lists move: the figures above were current when Expert Reviews published them (September 2024 for Panda, April 2025 for Simba). Use them for the gaps between sizes rather than as today’s price. If you want to time the purchase, our guide to the best time to buy a mattress covers when the biggest sales land.

Sheets and toppers are sold by UK size name, and as long as your mattress is a standard UK size, a “king” fitted sheet bought in a British shop will fit a British king. The two things that go wrong are the ones we’ve already flagged — Euro and US sizes — and depth.

Modern boxed mattresses are deep. The Simba Hybrid Pro is 28cm, the OTTY Original Hybrid 25cm, the Nectar UK Memory Foam around 25cm and the Emma Hybrid Original 22cm, according to the specs in our UK guide. Older fitted sheets were often made for thinner sprung mattresses, and if you add a topper on top, you can easily exceed the pocket depth. Check the fitted sheet’s stated depth before buying, and if you are adding a topper, add its thickness to the mattress depth. Our best mattress topper guide lists topper thicknesses so you can do the sum.

The same applies to mattress protectors, which grip the sides like a fitted sheet. And for zip-and-link super kings, look for a fitted sheet or topper that spans both halves, which hides the join and stops the two mattresses drifting apart.

Finally, if you’re still deciding what kind of mattress to put in your new size, our how to choose a mattress guide walks through firmness, sleeping position and materials, and the best mattress UK ranking turns that into seven specific beds you can buy in every size on this page.