UK Mattress Size Guide: Every Size in cm and Inches
UK mattress sizes run from Small Single at 75 × 190 cm up to Emperor at 200 × 200 cm. The number people get wrong is not the width — it is the length. A standard UK mattress is 190 cm long. A standard European one is 200 cm.
The full chart
| Name | Imperial | Centimetres | Inches |
|---|---|---|---|
| Small single | 2'6" | 75 × 190 cm | 30" × 75" |
| Single | 3'0" | 90 × 190 cm | 36" × 75" |
| Small double | 4'0" | 120 × 190 cm | 48" × 75" |
| Double | 4'6" | 135 × 190 cm | 54" × 75" |
| King | 5'0" | 150 × 200 cm | 60" × 78" |
| Super king | 6'0" | 180 × 200 cm | 72" × 78" |
| Emperor | 6'6" | 200 × 200 cm | 78" × 78" |
Small single through to Double are 190 cm long. King and above are 200 cm. That step happens between Double and King and it catches people out when they move up a size and keep the old bed frame.
Emperor is not a standard
Small single to Super king are settled sizes that every British bedmaker builds to. Emperor is not. Different manufacturers sell 180 × 200, 200 × 200 and 215 × 215 under the same name. Ours is 200 × 200 cm. If you are replacing an Emperor from another maker, measure it — do not assume.
Why UK and European sizes do not swap
A UK Double is 135 × 190 cm. The nearest European size is 140 × 200 cm. That is 5 cm wider and 10 cm longer, so a UK double mattress in a European frame leaves a gap you can put your arm into, and a European mattress will not go into a UK frame at all.
This matters most with imported and flat-pack frames. If your bed came from a continental retailer, measure the internal opening before you order anything. Our EU and IKEA size conversion guide lists the pairs side by side.
Measure the frame, not the old mattress
Old mattresses spread. A fifteen-year-old double can measure 138 cm across because the sides have bowed outward under years of edge-sitting. Measure the internal opening of the frame instead: the clear space between the side rails, and between the head and foot boards.
- Measure at three points along the width and take the smallest.
- Measure the diagonal too. If the two diagonals differ by more than a centimetre, the frame is out of square and a snug mattress will fight it.
- Note the depth of the surround. A frame with a 20 cm surround and a 38 cm mattress will bury the bottom half of the mattress and change how it feels at the edge.
What if nothing on the chart fits
Then buy the mattress to fit the bed rather than the other way round. Antique frames, boat berths, caravans, attic rooms with a sloping wall and bespoke joinery all sit outside these seven sizes, and cutting to size is not a premium service in our factory — it is the same production line.
See our made-to-measure mattress, or read how to measure your bed for a custom mattress first.
Common questions
Is a UK King the same as a US King?
No. A UK King is 150 × 200 cm. A US King is roughly 193 × 203 cm, which is closer to our Emperor in width. US bedding will not fit UK beds.
What is a three-quarter bed?
An older name for the Small double, 120 × 190 cm. You will see it on frames from the 1950s and 60s.
How much tolerance is there?
Mattresses are soft goods and every maker works to a tolerance, typically ± 1 to 2 cm. If your frame opening is exactly the mattress size with nothing to spare, order 1 cm under rather than dead on.