Sealy Posture Balance Super King Mattress
The Sealy Posture Balance comes in five UK sizes, from Single up to Super King.
- Firm feel with cushioned comfort
- Open-cell foam for breathability
- Hypoallergenic fibre fillings
£956.25
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Sealy Posture Balance Mattress
More available sizes
Mattress details
Mattress
Sealy Posture Balance Mattress
Size
Firmness
Firm
Construction
Depth (cm)
Layers
3
Layer Details
PostureTech 2.0 pocket springs
Pocket springs made with higher gauge wire sit at the heart of this firmer design. They give the mattress its supportive base feel, which suits sleepers who like a firm, steady surface.
MicroCell
An open-cell foam that is durable and resilient, with a soft feel. The open structure helps air move through, so it should sleep less warm than a dense foam.
OptiForm firm foam
A double layer of firm foam that gently cushions and adapts to your body. It adds some give on top of the firm feel, so the surface isn't hard.
Layer details from mattressman.co.uk product page, October 2026.
Key benefits
- Maximum space for two: With 90cm each for two people sharing, you both get the same width as a full UK single to yourself.
- Distance beats any comfort layer: If your partner shifts constantly through the night, 30cm more width than a UK king does more than any material could.
- Room for night-time visitors: Children who wander in at 3am, or a large dog with settled habits, can join you without pushing anyone to the edge.
- Fills a large master properly: In a period property or big new build bedroom, a UK king can look undersized; the UK super king holds the room.
- Know your room first: Allow at least 3m x 2.9m so you can still open drawers and walk round the bed comfortably.
This size suits you if...
You share the bed every night and want the most space a standard UK size offers, your partner is genuinely restless and you have learned that distance matters more than mattress feel, or children and pets regularly end up in with you and everyone still needs their share of the width.
Consider another size if...
Your bedroom is smaller than the 3m x 2.9m we suggest as a minimum for this size. The Sealy Posture Balance in a UK king would suit you better, needing at least 2.7m x 2.9m while staying the same 200cm length.
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FAQ's
How much bigger is the Sealy Posture Balance super king than the king?
The UK super king is 30cm wider than the UK king, and the two are the same length. That extra width all goes into sleeping space, so a couple gets 90cm each rather than sharing a narrower surface. If a restless partner wakes you, that 30cm is usually what makes the difference.
Will the Sealy Posture Balance super king fit in my bedroom?
We suggest a room of at least 3m x 2.9m for a UK super king, which leaves space to walk round the bed and open wardrobes. This is our guidance rather than Sealy's. In a loft conversion, check the ceiling slope too, since it can decide which wall the bed sits against.
Can the Sealy Posture Balance super king get up a narrow staircase?
A 180 x 200cm mattress is awkward on tight landing turns, so measure your stairwell, door swings and any corners before ordering. Sealy publishes limited specification detail for this model, including weight, so ask the retailer how it arrives. Some larger mattresses come rolled, which makes the move upstairs far simpler.
Is there room for children in a super king Sealy Posture Balance?
Yes, this is where the size makes sense. Two adults get 90cm each, so when a child pads in during the night there is genuine space to absorb them without anyone teetering on the edge. The same logic applies if a large dog treats your bed as its own.
What should I check before buying this mattress in a super king?
Two things. First, the practical: your room meets the 3m x 2.9m minimum we suggest, the mattress can make it upstairs, and you have budgeted for super king bedding. Second, the mattress itself: Sealy publishes little about this model's firmness or materials, so read the retailer listing carefully before committing.