Silentnight Breathe Gel Memory Foam King Size Mattress
The Silentnight Breathe Gel Memory Foam Mattress is a medium firm, all-foam mattress at 18cm deep, which makes it a little shallower than the deep hybrid styles you may have seen elsewhere, but simpler to move and fine on most bed bases.
- Cool gel foam for warm sleepers
- Eases pressure at hips & shoulders
- Edge-to-edge support, no roll-together
£349
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Silentnight Breathe Gel Memory Foam Mattress
More available sizes
Mattress details
Mattress
Silentnight Breathe Gel Memory Foam Mattress
Size
Firmness
Medium Firm
Construction
Foam
Rolled
Memory Foam
Gel
Depth (cm)
18
Layers
3
Layer Details
Soft Touch Quilted Cover
A quilted fabric finish that gives a smooth, breathable sleep surface. It's the first thing you'll feel, and it's designed for comfort rather than a taut, flat top.
Cool Gel Memory Foam
This layer enhances pressure relief and support, which means less strain on hips and shoulders as you settle in. It also regulates body temperature better than standard memory foam, a genuine help if you tend to sleep warm.
Supportive Miratex® Foam
Miratex foam conforms to the shape of your body as you sleep, giving maximum comfort. It provides edge to edge support with no roll together, so you get the full sleeping surface rather than drifting towards the middle.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- 75cm each for two sharers: The UK king's 150cm width gives each of you 75cm, so a restless partner or an early alarm feels further away than it does on a double.
- Edge to edge support across the full 150cm: The Miratex foam layer supports right to the sides with no roll together, which means the extra width you're paying for is all usable sleeping space.
- Extra length for taller sleepers: At 200cm the UK king is 10cm longer than the UK double, welcome if either of you is approaching six foot and used to toes at the edge.
- Cool gel across a bigger surface: Two people sharing generate more heat than one, and the gel memory foam layer regulates body temperature better than standard memory foam does.
- An 18cm all-foam build that's easier to handle: The slimmer depth makes a king sized mattress less awkward to manoeuvre up stairs and around landings than a deep hybrid would be.
This size suits you if...
You share the bed every night and a double has started to feel cramped, especially if one of you keeps different hours and disturbs the other getting in or out. It's also the size to pick if either sleeper is tall enough to appreciate the 200cm length, or if the dog has quietly become a permanent third occupant taking more than its share.
Consider another size if...
Your bedroom falls short of the 2.7m x 2.9m we suggest for a UK king, or you sleep alone and don't need the width. We'd recommend the UK double instead, which needs a smaller room, at least 2.6m x 2.8m by our guidance.
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FAQ's
Is the Silentnight Breathe Gel UK king big enough for a couple?
Yes, comfortably for most. At 150 x 200cm it gives each sharer 75cm of width, and the Miratex foam layer supports edge to edge with no roll together, so neither of you drifts towards the middle. Heavier or taller sleepers should note the 18cm depth is slimmer than many mattresses.
What room size do I need for the Silentnight Breathe Gel in a UK king?
We suggest a room of at least 2.7m x 2.9m, with 3.2m x 3.2m feeling comfortable once wardrobes and bedside tables go in. New build master bedrooms can be tighter than they first appear, so measure with furniture in place before committing to a king.
Is the UK king long enough for someone over six foot?
It helps. The UK king is 200cm long, which is 10cm more than the UK double, and for anyone approaching six foot that extra length is often the real reason to size up. This mattress isn't made in a UK super king, so the king is the longest and widest option available.
How much bigger is the king than the double in this mattress?
The UK king is 15cm wider and 10cm longer than the UK double. That's 75cm of width each for two sharers, enough that one partner shifting position or leaving early for work disturbs the other less. In imperial terms the king measures 5ft x 6ft 6in.
Where can I buy the Silentnight Breathe Gel mattress in a UK king?
Compare the retailers listed on this page; the prices shown here are updated as retailers change them, so it's worth checking back if you're not buying today. Stock of individual sizes can shift, so confirm the UK king specifically is what's in your basket before checkout.