Duvet and comforter sizes
11 standard bedding sizes with their real dimensions and how far each one hangs over the bed.
A duvet is much wider than the bed
This is the part that surprises people measuring for the first time. A UK double bed is 135 cm wide and a UK double duvet is 200 — 65 cm wider, dropping 32.5 cm down each side. Buying bedding to match the mattress is the most common way to end up with a duvet that is too small.
Every standard size lands between 22 and 40 cm of overhang per side. Below about 25 the cover rides up whenever someone turns over, which is what "the duvet is too small" almost always means in practice: right for the bed, wrong for two people.
The names do not cross the Atlantic
A UK king duvet is 225 cm wide. A US king comforter is 264. That is 39 cm — more than a foot — under one word. The mattresses have the same problem, and it compounds: a British king bed with an American king comforter is swamped, and the reverse leaves the mattress bare on both sides.
United Kingdom
| Size | Centimetres | Inches | Bed width | Overhang each side |
|---|---|---|---|---|
| Single | 135 × 200 | 53 × 79 | 90 cm | 22.5 cm |
| Double | 200 × 200 | 79 × 79 | 135 cm | 32.5 cm |
| King | 225 × 220 | 89 × 87 | 150 cm | 37.5 cm |
| Super King | 260 × 220 | 102 × 87 | 180 cm | 40.0 cm |
| Emperor | 290 × 235 | 114 × 93 | 200 cm | 45.0 cm |
North America
| Size | Centimetres | Inches | Bed width | Overhang each side |
|---|---|---|---|---|
| Twin | 173 × 224 | 68 × 88 | 97 cm | 38.1 cm |
| Twin XL | 173 × 234 | 68 × 92 | 97 cm | 38.1 cm |
| Full | 206 × 224 | 81 × 88 | 137 cm | 34.3 cm |
| Queen | 224 × 244 | 88 × 96 | 152 cm | 35.6 cm |
| King | 264 × 244 | 104 × 96 | 193 cm | 35.6 cm |
| California King | 264 × 254 | 104 × 100 | 183 cm | 40.6 cm |
Duvet, cover, comforter
The words describe different objects. A duvet is the insert — the filled quilt — and goes inside a duvet cover, which is washed separately; this is the British and continental arrangement. A comforter is the American equivalent sold as one finished quilted piece, usually used with a flat sheet underneath rather than a cover over it. A cover is bought to match the duvet it goes on, never the bed, which is the other common sizing mistake.
Tog is warmth, not thickness
A tog rating measures thermal resistance and nothing else. A 13.5 tog down duvet is thinner and lighter than a 13.5 tog synthetic one, and they keep you equally warm — the filling decides the bulk, the tog decides the warmth.
| Tog | For |
|---|---|
| 4.5 and under | Summer, and rooms that stay above about 20 °C |
| 7–10.5 | Spring and autumn, or a warm bedroom year round |
| 12–13.5 | Winter in an unheated or lightly heated room — the usual single-duvet choice in Britain |
| 15 and over | Genuinely cold rooms, and rarely necessary in a modern insulated house |
An all-seasons duvet is two duvets — commonly 4.5 and 9 tog — with poppers to join them. Together they are 13.5, which is the arithmetic working exactly as it looks: tog values of stacked layers add.
The scale is not used in North America, where duvets and comforters are sold by season name or fill power. Fill power measures loft rather than warmth, so it is not convertible to tog: a high fill power tells you the down is good quality and springs back well, not how warm the finished duvet is.
Why the duvet is bigger than the bed, and by how much
A duvet has to drape, and the drop on each side is the whole reason the sizes do not match the mattress. A UK Double mattress is 135 cm wide and a Double duvet is 200 — 32.5 cm of overhang on each side once the bed is made. That is deliberate, and it is roughly the minimum that stops one sleeper stripping the other.
Which is why the standard advice for two people in a Double is to buy a King duvet on a Double bed. A King duvet is 225 cm, so on the same 135 cm mattress the drop goes to 45 cm a side — the extra width goes entirely into drape, the bed still looks made, and the nightly negotiation stops. Going the other way, a Double duvet on a King bed leaves 25 cm a side, which is not enough to stay put.