If you want the fast answer, a standard UK super king duvet cover measures 260 x 220 cm, or about 102 x 87 inches. It is made to fit a super king duvet of the same size and is typically paired with a UK super king bed measuring 180 x 200 cm. Easy on paper. Confusing in real life. Especially when king, super king, European sizes and mattress sizes all get mixed together. This guide clears that up quickly.
The exact UK measurements you need
For a standard UK setup, your duvet cover should match your duvet, not your mattress. If you are searching for super king size duvet dimensions in cm or want an overview of all duvet sizes, these are the key numbers to know.
| Item | Size in cm | Size in inches |
|---|---|---|
| Super king bed / mattress | 180 x 200 | 71 x 79 |
| Super king duvet | 260 x 220 | 102 x 87 |
| Super king duvet cover | 260 x 220 | 102 x 87 |
| Super king fitted sheet | 180 x 200 | 71 x 79 |
| Super king flat sheet | 305 x 275 | 120 x 108 |
One important note: fitted sheet depth can vary by mattress, so always check the depth as well as the width and length. That matters for sheets, not for duvet covers.
How super king sizing actually works
Here is the bit that saves you from a returns headache. A super king bed is 180 x 200 cm, but the duvet and duvet cover are much larger at 260 x 220 cm. That extra fabric is there for proper overhang at the sides and foot of the bed. In other words, your cover should not match the mattress size. It should match the duvet size.
For most UK shoppers, the right choice is simple: if you have a super king duvet, buy a super king duvet cover in 260 x 220 cm. If you have not bought the duvet yet, browse our duvets first, then match the cover to it. That keeps the fill sitting properly inside the cover and stops the bed from looking tight, lumpy or oddly short.
Comparing fabrics? See our guide to cotton sateen bedding to understand feel, sheen and breathability.
Common size mistakes to avoid
- Choosing a cover based on mattress size instead of duvet size.
- Buying a king duvet cover for a super king duvet.
- Assuming all brands use identical labels without checking the measurements.
- Forgetting that fitted sheet depth matters, even when width and length are correct.
- Thinking 240 x 220 cm is super king in the UK when it is usually king size.
Super king duvet cover FAQ
Will a king duvet cover fit a super king duvet?
No. A UK king duvet cover is usually 225 x 220 cm, while a super king duvet needs 260 x 220 cm. That missing width matters. A too-small cover can compress the duvet filling and make the bed feel uneven.
What size is a 240 x 220 duvet cover?
In the UK, 240 x 220 cm is usually a king size duvet cover, not a super king. It is a common size, but it is narrower than the standard UK super king cover.
What bed size is 240 x 220 cm?
240 x 220 cm is not a bed size. It refers to a duvet or duvet cover. In most UK bedding ranges, it is intended for a king bed setup.
What size is a 220 x 225 duvet?
That is effectively a king size duvet. Some retailers list the same measurement as 225 x 220 cm, while others reverse the numbers. Always check the full dimensions rather than relying on the label alone.
Is 180 x 200 super king?
Yes. In the UK, 180 x 200 cm is the standard super king mattress size.
What sheet size fits a super king bed?
A super king fitted sheet is usually 180 x 200 cm, matching the mattress. A flat sheet is commonly 305 x 275 cm. Just make sure the fitted sheet depth suits your mattress height.
If you are upgrading more than just the cover, keep the whole setup aligned. Match your duvet, duvet cover and sheets carefully, and shopping our bedding collection becomes a lot easier. That is exactly how better sleep should feel: simple, clear and drama-free.
