Mattress size finder
Height, sleepers and room width decide the size. The finder applies the rules and shows its reasoning.
Three things decide bed size, and height is the one people skip, because the conversation is always about width.
The rules it applies
Length. A mattress should be at least 10 to 15 centimetres longer than the tallest person. That caps the 190cm sizes at roughly 5'11" and the 200cm sizes at roughly 6'3".
Width. Two adults in a double get 67.5cm each, which is less than a single bed would give them. A king gives 75cm each and a super king 90cm, which is exactly a UK single each.
Floor space. Allow 60 to 75 centimetres each side to walk past and make the bed. Below about 60 the room stops working.
| Name | Centimetres | Imperial | Who it suits |
|---|---|---|---|
| Small single | 75 × 190 | 2'6" × 6'3" | Children, box rooms, cabin beds |
| Single | 90 × 190 | 3'0" × 6'3" | One adult, children, guest rooms |
| Small double | 120 × 190 | 4'0" × 6'3" | One adult with space, two at a squeeze |
| Double | 135 × 190 | 4'6" × 6'3" | Two adults. The UK default. |
| King | 150 × 200 | 5'0" × 6'6" | Two adults with room, or anyone over 6ft |
| Super king | 180 × 200 | 6'0" × 6'6" | Two adults, a child, or a dog |
| Emperor | 200 × 200 and up | 6'6" × 6'6" | Not standardised. Sizes vary by maker. |
Length changes at king
Small single, single, small double and double are all 190cm long. King and super king are 200.
So for a tall person, moving to a king is a length decision, available without going to super king width. On a frame with a footboard there is no overhang at all, which makes the limit absolute rather than approximate.
European and US sizes with the same names are different
This is where most sizing mistakes come from, and it catches people buying from IKEA and from imported ranges.
| Name | UK | Europe |
|---|---|---|
| Single | 90 × 190cm | 90 × 200cm |
| Double | 135 × 190cm | 140 × 200cm |
| King | 150 × 200cm | 160 × 200cm |
Every row differs, and the length differs as well as the width on singles and doubles. A European double is ten centimetres longer than a UK one, which is the part people miss.
A US queen is roughly 152 by 203cm, closest to a UK king. There is no UK queen size, so a listing offering one is using an imported name.
Depth is the measurement nobody checks
Bed sizes describe length and width. Depth is not standardised at all, and it is what decides whether your sheets fit.
Standard UK fitted sheets are cut for about 25 centimetres. Modern hybrids run 28 to 35, and a topper adds 5 to 10 on top of that.
Add the mattress depth to the topper depth and buy a few centimetres over, because the fabric has to fold under rather than merely reach the edge.
Check it will get into the room
The most common expensive mistake at the larger sizes.
A super king pocket sprung mattress can weigh 60 to 80 kilograms and does not bend. Forcing one round a stair turn can damage the spring unit permanently.
Measure doorways, stair width, the landing turn and any low ceiling over the stairs. A boxed mattress solves delivery; a traditional sprung one does not.
Zip and link is the answer where access is the problem, since two singles come up separately and each person can choose their own firmness. Note that zip and link singles are made at 90 by 200cm rather than 190, so two make a proper super king.
Related reading
Size guides
Bedding to match
How this site works
Nothing here is paid for by a brand. No manufacturer has copy approval, a preview, or the ability to change a score, and where a link earns a commission that never changes a ranking.
Where a brand does not publish a specification, that is stated rather than estimated, because an absent number is itself information. The corrections log and the products I will not recommend page are both public.