UK Bed Sizes Explained
The five standard UK bed sizes in centimetres, what the imperial names mean, and why the frame is always bigger than the number on the label.
UK bed sizes are names, not measurements
A "double" is not a description of a bed — it is a standard. The UK bed trade uses a fixed set of size names, and every mattress and every frame sold under one of those names is built to the same dimensions. That is what makes buying a frame and a mattress separately work at all: a double mattress from one retailer fits a double frame from another, because both are working to the same number. The names came from imperial measurements and are still sometimes written that way — a double is a 4ft6, a king is a 5ft — which is why the same bed can appear under two names on two sites.
The five UK sizes
These are mattress dimensions. Every figure below is the mattress, not the bed.
| Size | Imperial | Mattress | We stock |
|---|---|---|---|
| Single | 3ft | 90 × 190 cm | 7 beds |
| Small Double | 4ft | 120 × 190 cm | 6 beds |
| Double | 4ft6 | 135 × 190 cm | 23 beds |
| King Size | 5ft | 150 × 200 cm | 22 beds |
| Super King | 6ft | 180 × 200 cm | 1 bed |
Standard sizing. A specific product's own stated dimensions always take precedence.
A frame is bigger than its mattress
The sizes above are the mattress. The frame around it is always larger, and by an amount that is not standard — it depends on the thickness of the side rails, whether there is a surround, and how the headboard is built. Each frame states its own external width. This is the mistake that causes a bed not to fit. The mattress size tells you what to buy to go on it; the frame dimensions on the product page tell you whether it goes in the room. Plan with the second.
What we stock
Beds are available in single, small double, double, king size and super king; the size pages below show what is available in each.
Common questions
What size is a UK double bed?
A double mattress is 135 cm wide and 190 cm long, sometimes written as 4ft6. The frame around it is larger and varies by design.
What is the difference between a double and a king size?
A king size mattress is 15 cm wider and 10 cm longer than a double — 150 × 200 cm against 135 × 190 cm.
What is a small double?
A small double mattress is 120 × 190 cm — 15 cm narrower than a double, and the same length. It is also sold as a "4ft" or a "queen" by some retailers, which is a different size from a US queen.
Will any double mattress fit any double bed frame?
Yes, as far as size goes — both are built to the same standard. Depth is the exception: it is not standardised, and on a bunk bed it is a safety limit rather than a preference.
Do I measure the mattress size or the bed size for my room?
The bed. The mattress size tells you which mattress to buy; the frame's own dimensions, on its product page, tell you whether it fits the room.
