Single, small double, double or king?
The difference between the common UK sizes is mostly width. Here is how much room each gives, and when to step up.
Checked against UK retailer and maker guides on 21 October 2026.
| Size | Mattress | Width per person if two share | Who it suits (sources) |
|---|---|---|---|
| Single | 90 × 190 cm | – | One sleeper; box rooms and guest rooms (MattressNextDay) |
| Small double | 120 × 190 cm | 60 cm | One adult who wants more room (BedGuide); snug for two (Which?) |
| Double | 135 × 190 cm | 67.5 cm | Two average adults, though “not much wiggle room” (Which?) |
| King | 150 × 200 cm | 75 cm | Couples who want more space, or taller sleepers (MattressNextDay) |
| Super king | 180 × 200 cm | 90 cm | Two adults who want the most space (BedGuide) |
Width per person is simple division of the mattress width. BedGuide gives the same figure for a double: about 67 cm each.
Two quick tests
- Length: MattressNextDay’s rule of thumb is a bed at least 10 cm longer than the tallest person using it. So anyone over 180 cm tall is better on a 200 cm king or super king than a 190 cm double.
- Width: Which? suggests both of you should be able to lie on your back with your hands behind your head without your elbows touching each other or the edge of the bed.
Double vs king
A king is 15 cm wider and 10 cm longer than a double. MattressNextDay’s view is that if the room is big enough, the extra space is worth it. Check the room first: how much space each bed needs.
Small double
A small double is 120 × 190 cm, the same length as a double but 15 cm narrower (Which?). It is also sold as a “queen” or “three quarter” (MyBedFrames), and Dunelm calls it a “¾ double”. Bedding is less widely stocked than for a double, so check sheets before you buy the bed.
Questions
Is a double bed big enough for two?
For two average adults, yes, but Which? says there might not be much wiggle room. A king gives each person 75 cm instead of 67.5 cm.
How much bigger is a king than a double?
15 cm wider and 10 cm longer: 150 × 200 cm against 135 × 190 cm.
Where these numbers come from
- Which?: UK bed sizes, bed and mattress size guide
- BedGuide: UK bed sizes
- MattressNextDay: UK bed and mattress size guide
- MyBedFrames: UK bed sizes guide
- Dunelm: bed linen buying guide
Checked 21 October 2026. Makers round sizes differently, so always check the dimensions on the product you're buying.