Sealy Advantage Memory Essential Super King Mattress
The Sealy Advantage Memory Essential pairs a MemorySense memory foam comfort layer with PostureTech Core Support Springs, which means you get that slow-sinking foam feel with a bit more bounce and support underneath than an all-foam design.
- Eases pressure at shoulders & hips
- Suits back & stomach sleepers
- Spring core lets air flow through
£569
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Sealy Advantage Memory Essential Mattress
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Mattress details
Mattress
Sealy Advantage Memory Essential Mattress
Size
Firmness
Medium Firm
Construction
Foam
Memory Foam
Depth (cm)
27
Layers
2
Layer Details
Comfort Layer
A layer of MemorySense memory foam sits on top, which means it moulds to your body shape and eases pressure on your shoulders and hips. It gives you that gentle cradling feel memory foam is known for.
Support System
Beneath the foam, PostureTech Core Support Springs do the structural work, keeping your spine aligned and adding responsiveness so you don't feel stuck when changing position. The springs also allow more airflow than a solid foam base.
Layer details from mattressonline.co.uk product page, September 2026.
Key benefits
- 90cm of width each: Two sharers get 90cm apiece, which means you can spread out fully without your elbow ever finding the person next to you.
- Distance softens motion transfer: The PostureTech springs pass on slightly more movement than all-foam designs, but at this width a restless partner is far enough away that most of it never reaches you.
- Room for night-time visitors: When children or a large dog treat your bed as theirs, 180cm of width means everyone keeps a genuine share rather than clinging to an edge.
- A king-length bed, 30cm wider: The UK super king is 30cm wider than the UK king but exactly the same length, so you gain sprawling room without needing a longer wall.
- Memory foam that stays breathable at scale: A big slab of solid foam can hold heat, so the spring core letting air move through matters more at this size than any other.
- Live pricing on this page: Super king prices shift often, so compare the retailers listed here rather than a figure you saw last week.
This size suits you if...
You share the bed every night and one of you moves around enough to wake the other, or children and pets regularly join you and a UK king already feels crowded. It also makes sense if you have a large master bedroom, perhaps in a period property, where a smaller bed would look lost against the wall.
Consider another size if...
Your bedroom is smaller than the 3m x 2.9m we suggest as a minimum, or you sleep alone. We'd recommend the UK king instead: it's the same length, and we suggest at least 2.7m x 2.9m for it.
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FAQ's
What size room do I need for the Sealy Advantage Memory Essential super king?
We suggest a minimum of 3m x 2.9m, and around 3.5m x 3.2m feels comfortable, leaving space to walk round both sides and open drawers. This is our guidance rather than Sealy's. Before you commit, check the door swing clears the footboard end and that any landing turns can take a mattress this wide.
Should I get this mattress in a UK king or a UK super king?
The UK super king is 30cm wider than the UK king and the same length, so the question is purely about width. If a restless partner, children or pets are part of your nights, the extra 30cm is the whole point. If your room is under 3m wide, the UK king is the sensible call.
Is the super king good for couples where one partner is restless?
Yes, and arguably it helps more here than usual. The PostureTech springs in this mattress can transmit a little movement, something one owner review mentioned. With 90cm of width each, though, most of that movement happens too far away to disturb you, so the size itself does much of the work.
What are the dimensions of the Sealy Advantage Memory Essential super king?
It measures 180 x 200cm, which is 6ft x 6ft 6in. That's the largest size this mattress is made in, 45cm wider and 10cm longer than the UK double. Width, length and the room you'll need are the only things that change; the medium firm feel and 27cm depth are the same in every size.
Is this super king big enough to share with kids or a dog?
Realistically, yes. At 180cm wide it matches two UK singles side by side, so a child arriving at 3am, or a large dog who considers the bed shared territory, still leaves both adults a workable stretch of mattress. The memory foam layer cradles smaller bodies gently too, though very light sleepers may find it a touch firm.