Sealy Advantage Quartz Memory King Size Mattress
The Sealy Advantage Quartz Memory Mattress combines a MemorySense foam layer with PostureTech CS springs, which means you get that slow, cradling memory foam feel on top with proper spring support underneath rather than an all-foam base.
- Memory foam eases pressure points
- Stable edges, no roll-off feeling
- Twice-tempered springs hold their shape
£579
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Sealy Advantage Quartz Memory Mattress
More available sizes
Mattress details
Mattress
Sealy Advantage Quartz Memory Mattress
Size
Firmness
Medium Firm
Construction
Foam
Memory Foam
Depth (cm)
27
Layers
4
Layer Details
Quilted Cover
The cover is stitched together with the fillings to create a patterned comfort quilt, which means the surface has a soft, cushioned feel built in rather than a flat top. It's the first thing you'll notice when you lie down.
MemorySense Foam
This memory foam layer adapts to your body position, cocooning you and easing pressure at the shoulders and hips. In practice, that means less tossing and turning to get comfortable.
PostureTech CS Springs
These springs respond to your body weight to give deep-down support, so heavier areas get more pushback than lighter ones. They're twice tempered, meaning the steel is heat-treated twice to stay resilient over years of use.
EdgeGuard
A high-density foam strip reinforces the springs around the perimeter, extending their lifespan. You'll feel this as a firmer, more supportive edge, useful if you sit on the bed or share it and need the full width.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- 75cm of width each: Two people sharing get 75cm each, which means fewer elbows and less shuffling to reclaim your side during the night.
- Memory foam that dampens movement: The MemorySense layer absorbs motion where springs alone pass it along, so an early alarm on one side is less likely to wake the other.
- Extra length for taller sleepers: At 200cm, the UK king is 10cm longer than the UK double, a real difference if either of you finds your feet at the end of the bed.
- A firm edge across a wide bed: EdgeGuard reinforcement means the outer strip of those 150cm stays supportive, so you can spread out to the sides rather than gravitating to the middle.
- Medium Firm across the full width: The PostureTech CS springs respond to each sleeper's weight independently, so a heavier and lighter partner both get appropriate pushback on their own side.
This size suits you if...
You share the bed every night and a double has started to feel cramped, especially if one of you gets up hours before the other and the disturbance carries across. It's also the sensible pick if either partner is tall, since the 200cm length gives feet somewhere to go, or if a dog has quietly become a permanent third occupant and you need the width back.
Consider another size if...
Your bedroom falls short of the 2.7m x 2.9m we suggest for a UK king, or you want the maximum sprawl money can buy. For small rooms we'd recommend the UK double, allowing at least 2.6m x 2.8m; for space, the UK super king needs at least 3m x 2.9m.
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FAQ's
Is the Sealy Advantage Quartz UK king big enough for a couple?
Comfortably, for most. At 150 x 200cm you get 75cm each for two people sharing, and the EdgeGuard reinforcement keeps the perimeter firm so all of that width is usable. If one of you sleeps in a starfish or a dog joins you most nights, the UK super king is 30cm wider.
How much space does each person get on a king size Sealy Advantage Quartz?
75cm each for two people sharing, which is 15cm more combined width than the UK double offers. In practice that's the difference between adjusting your position freely and waking your partner every time you turn, particularly with the memory foam layer softening any movement that does travel.
Will the Sealy Advantage Quartz UK king fit in my bedroom?
We suggest a room of at least 2.7m x 2.9m for a UK king, with 3.2m x 3.2m feeling comfortable. Measure after accounting for wardrobes and door swing; new build master bedrooms in particular can shrink quickly once fitted furniture goes in. If you're tight, the UK double needs at least 2.6m x 2.8m.
Is the UK king Sealy Advantage Quartz long enough for tall sleepers?
At 200cm (5ft x 6ft 6in overall), it's 10cm longer than the UK double, and that length is often the real reason taller sleepers upgrade rather than the width. Anyone approaching or over six foot should notice the difference immediately. The UK super king is the same length, so sizing up again only adds width.
Should I buy the Sealy Advantage Quartz in a king or super king?
The UK king suits most couples: plenty of space without demanding a huge room. The UK super king is 30cm wider but needs a room of at least 3m x 2.9m, so it only makes sense if you have the floor space and genuinely want that extra sprawl. Compare the retailers listed on this page for current pricing on both.