UK mattresses come in six standard sizes: small single 75 x 190cm, single 90 x 190cm, small double 120 x 190cm, double 135 x 190cm, king 150 x 200cm and super king 180 x 200cm. Above those sits the emperor at 200 x 200cm. British sizes are shorter than European ones and do not match American names, so a “double” or a “queen” bought for a frame from abroad often will not fit.
UK mattress sizes in cm and feet
The six standard sizes below are those listed in the National Bed Federation’s size guide, and the emperor sizes are as UK makers list them. The last column counts how many of the 403 mattresses we review for UK readers are sold in each size (October 2026).
| Size | Centimetres | Feet and inches | Width each if two share | Mattresses we review sold in it |
|---|---|---|---|---|
| Small single | 75 x 190 | 2ft 6in x 6ft 3in | One sleeper | 122 (30%) |
| Single | 90 x 190 | 3ft x 6ft 3in | One sleeper | 330 (82%) |
| Small double | 120 x 190 | 4ft x 6ft 3in | 60cm | 243 (60%) |
| Double | 135 x 190 | 4ft 6in x 6ft 3in | 67.5cm | 320 (79%) |
| King | 150 x 200 | 5ft x 6ft 6in | 75cm | 322 (80%) |
| Super king | 180 x 200 | 6ft x 6ft 6in | 90cm | 234 (58%) |
| Emperor | 200 x 200 | 6ft 6in x 6ft 6in | 100cm | 19 (5%) |
| Large emperor | 215 x 215 | 7ft x 7ft | 107.5cm | 9 (2%) |
The imperial column explains why one size can carry two sets of figures. A straight conversion makes 4ft 6in 137cm and 5ft x 6ft 6in 152 x 198cm, and some makers still sell those exact sizes: Abaca lists its Rhossili UK king at 152 x 198cm. TEMPUR asks buyers to allow a tolerance of plus or minus 2cm on its mattresses, so a couple of centimetres either way is normal. A 10cm difference means a different size.
Single and small single mattresses
A UK single mattress is 90 x 190cm (3ft x 6ft 3in), and a small single is 75 x 190cm (2ft 6in x 6ft 3in). The single is the most widely made size, available in 330 of the mattresses we track. The small single appears in fewer than a third, nearly three quarters of those from budget makers such as Starlight Beds and Aspire, because it is a common size for bunk beds, cabin beds and box rooms.
On a single, check the length. The NBF’s rule of thumb is a bed at least 10cm longer than the tallest person sleeping in it, which caps a 190cm single at about 180cm (5ft 11in). Taller teenagers and adults are better on a 90 x 200cm long single, which 48 of our mattresses come in and which is also a standard width for adjustable beds. Some children’s beds take a 75 x 175cm “shorty”, so measure a mid-sleeper before ordering. The Aspire Invigorate below is sold in both the small single and the single. Our best single mattresses ranking shows which models also come in the smaller and longer singles.
Aspire Invigorate Pocket Memory Foam Hybrid
A 23cm UK-made rolled hybrid with Pocket+ springs, memory foam and a standard or cooling cover.
Small double, 4ft and three-quarter beds
A small double mattress is 120 x 190cm, or 4ft x 6ft 3in, and the same mattress is sold as a 4ft, a three-quarter or a 3/4 bed. It is roomy for one adult and tight for two, at 60cm each. Its real advantage is floor space, since it leaves 15cm more than a double, enough in a box room to decide whether a wardrobe door opens.
The saving is usually small, too. Of the 235 models in our catalogue sold in both sizes, 126 cost exactly the same in both sizes, 100 are cheaper in the small double and 9 are dearer (prices checked October 2026). Some makers also sell a 120 x 200cm “long small double” for adjustable and continental bases, which is 10cm too long for a UK 4ft frame. Our best small double mattresses page ranks models made in the true 120 x 190cm size, and the Aspire Natural Wool Pocket Eco Hybrid below is one of them.
Aspire Natural Wool Pocket Eco Hybrid
A rolled 23cm hybrid made in the UK, with a wool comfort layer over Pocket+ springs and recycled eco foam.
Double, king and super king for couples
A UK double is 135 x 190cm (4ft 6in x 6ft 3in), a king 150 x 200cm (5ft x 6ft 6in) and a super king 180 x 200cm (6ft x 6ft 6in). Going from a double to a king adds 15cm of width and 10cm of length, which takes each sleeper from 67.5cm to 75cm and lifts the height limit to about 190cm. A super king adds another 30cm, 90cm each, and is the size to consider if a child or a dog regularly joins you.
The step up costs less than most people expect. Comparing the same mattress in both sizes, a king costs a median 13% more than a double (307 models) and a super king a median 17% more than a king (226 models). The big jump is from single to double, a median 32%, and current offers from the brands we cover are on our discount codes page. Our best double, best king size and best super king mattress comparisons rank the models in each size.
Simba Hybrid Pro Mattress
The Simba Hybrid Pro is a 28cm wool-topped hybrid with up to 4,800 springs, built for couples and back sleepers.
Emperor and the biggest mattress sizes
The widest mattress sold as a standard UK size is the emperor, 200 x 200cm or 6ft 6in square, listed by Vispring and Woolroom among others. Woolroom’s Standen is an all-wool mattress in that size. French Bedroom goes further with a 215 x 215cm (7ft x 7ft) “large emperor” and notes that its emperors are generally larger than the standard UK size, so on this size always ask for the exact measurement.
Choice is thin at the top. Only 19 mattresses in our catalogue come in 200 x 200cm and 9 in 215 x 215cm, mostly from premium makers, although OTTY and Panda London also list the emperor. Weight is the other catch, with TEMPUR giving 48 to 51kg unboxed for an emperor TEMPUR PRO SmartCool. If you want room for two people with different needs rather than sheer width, two 90 x 200cm singles make a 180 x 200cm bed, which is how zip-and-link and dual adjustable beds let each sleeper pick a firmness.
How UK sizes compare with European and US sizes
UK mattresses are shorter than European ones and named differently from American ones. Every common European size is 200cm long, with a 140 x 200cm double and a 160 x 200cm king. The National Bed Federation puts the gap bluntly in its size guide: “Top of the league are Belgium, Greece, Holland, Iceland, Finland and Switzerland where most people sleep in a roomy 160cm by 200cm bed. By contrast we Brits still buy more 135cm by 190cm beds.”
| UK size | UK (cm) | Closest European size (cm) | Closest US size |
|---|---|---|---|
| Small single | 75 x 190 | 80 x 200 | No equivalent |
| Single | 90 x 190 | 90 x 200 | Twin, 38 to 39 x 75in (97 to 99 x 191cm) |
| Small double | 120 x 190 | No common equivalent | No equivalent |
| Double | 135 x 190 | 140 x 200 | Full, 53 to 54 x 75in (135 to 137 x 191cm) |
| King | 150 x 200 | 160 x 200 | Queen, 60 x 80in (152 x 203cm) |
| Super king | 180 x 200 | 180 x 200 (the same) | King, 76 x 80in (193 x 203cm) |
European and US sizes are taken from Vispring’s size guide, which covers all three markets, with the US queen and full checked against Casper’s size chart. The super king is the one size that matches across the Channel.
“Queen” is where shoppers go wrong most often. The National Bed Federation’s guide uses it for the 120 x 190cm small double, Simba sells a 160 x 200cm “EU Queen”, and an American queen is 152 x 203cm. A US queen frame is therefore 2cm wider and 3cm longer than a UK king, so a UK king mattress sits slightly loose in it. In the UK, American sizes turn up mostly on air beds, and one model each from Intex, Bestway, Hi-Gear and Active Era in our air mattress comparison comes in the 152 x 203cm queen.
IKEA now lists its main UK ranges, such as MALM and VALEVÅG, in British sizes, but a few frames, such as the NORDLI with storage, still come in 140 x 200 and 160 x 200cm. Buy the mattress to the frame, not to its name. Alongside five of the UK sizes, the Simba Hybrid is also made in 90 x 200, 140 x 200 and 160 x 200cm.
Simba Hybrid Mattress
The Simba Hybrid is a 25cm medium-firm mattress pairing 1,900 Aerocoil microsprings with a nine-zone foam base, for most sleepers.
How to measure the frame, the room and the depth
Measure the space the mattress sits in, not the outside of the bed. Frames are sold by the mattress they take, and their outer dimensions are larger: IKEA’s MALM high bed frame for a 150 x 200cm king measures 166 x 209cm overall. The British and European standard BS EN 1334 sets out how beds and mattresses are measured and the tolerances between them.
- Inside the frame. Width and length between the rails, where the mattress rests.
- Outside the frame. The full footprint with the headboard, for the room.
- Depth. Your mattress at its highest point, plus any topper, for the sheets.
- The way in. Doorways, landing and the turn of the stairs, or choose a rolled mattress in a box.
Which size fits your bedroom
England’s Nationally Described Space Standard sets minimum widths for bedrooms in new homes, 2.15m for a single bedroom, 2.75m for the main double and 2.55m for any other double. The table shows the floor left on each side of the mattress in those rooms, with the bed centred and the headboard on the end wall. Deduct half the frame’s extra width, about 8cm a side on the MALM.
| Mattress | Room 2.15m wide | Room 2.55m wide | Room 2.75m wide |
|---|---|---|---|
| Single, 90cm | 62.5cm a side | 82.5cm a side | 92.5cm a side |
| Small double, 120cm | 47.5cm a side | 67.5cm a side | 77.5cm a side |
| Double, 135cm | 40cm a side | 60cm a side | 70cm a side |
| King, 150cm | 32.5cm a side | 52.5cm a side | 62.5cm a side |
| Super king, 180cm | 17.5cm a side | 37.5cm a side | 47.5cm a side |
| Emperor, 200cm | 7.5cm a side | 27.5cm a side | 37.5cm a side |
In our view a bedside table and a person stop fitting side by side once the gap, frame included, drops below about 40cm. On that basis a king is the largest sensible bed for a 2.55m second bedroom, and a super king needs at least the full 2.75m, with more to spare only above that.
Mattress depth and fitted sheets
Depth decides the fitted sheet. Belledorm’s sheet range shows the usual UK bands, with standard fitted sheets for mattresses 8 to 25cm deep, extra-deep sheets up to 38cm and ultra-deep up to 46cm. The median mattress we review is 25cm deep, right at the limit of a standard sheet, and 149 of the 364 with a stated depth (41%) are deeper, mostly hybrids and pillow tops such as the 28cm Simba Hybrid Pro. A 7cm topper on a 25cm mattress calls for a 38cm sheet, and the topper has to match the mattress size too, which is why we rank double, king size and super king toppers separately.
Our verdict
For most British homes the choice narrows to three sizes: a single for one sleeper under about 180cm, a king for most couples and anyone taller, and a super king for couples with a main bedroom of 2.75m or more. Choose a small double for the room rather than the price, since on just over half the models we review it costs the same as a double. Trust the inside of your frame over any size name, especially one labelled queen. Once the size is settled, our guide to choosing a mattress covers firmness and construction, our best mattresses ranking has the shortlist, and the full mattress catalogue lets you filter by size.
Frequently asked questions
What size mattress does one adult need?
A UK single of 90 x 190cm suits most adults under about 180cm tall. Taller sleepers should look at a 90 x 200cm long single, and anyone who likes to spread out will feel the difference on a 120 x 190cm small double.
What is the largest mattress size in the UK?
The emperor, at 200 x 200cm (6ft 6in square), is the largest standard UK mattress size. A few specialists make a 215 x 215cm large emperor, and Vispring builds bespoke sizes to order.
What size is a 4ft mattress?
A 4ft mattress measures 120 x 190cm, the UK small double.
Is a three-quarter bed the same as a small double?
Yes, a three-quarter (3/4) bed takes the same 120 x 190cm mattress as a 4ft small double. Measure an older frame first, because some makers still sell in-between widths such as a 107 x 190cm (3ft 6in) large single.
Will a UK king mattress fit a US queen bed frame?
Only loosely. An American queen frame takes a 152 x 203cm mattress, so a 150 x 200cm UK king leaves about 2cm across and 3cm at the foot, while a US queen mattress is too big for a UK king frame.
Can I put a 140 x 200cm mattress on a UK double frame?
No. A European 140 x 200cm double is 5cm wider and 10cm longer than the 135 x 190cm UK double, so it will not fit inside a UK double frame or divan.
Why do some mattresses measure 137 x 190cm or 152 x 198cm?
They are exact conversions of the imperial sizes (4ft 6in is 137cm, 5ft is 152cm, 6ft 6in is 198cm). Makers such as Abaca sell them for the same UK double and king beds as the rounded 135 x 190cm and 150 x 200cm sizes.
