MattressNextDay Ortho Support Foam King Size Mattress
The MattressNextDay Ortho Support Foam Mattress is an extra firm, all-foam orthopaedic mattress made in the UK.
- Extra-firm feel suits heavier builds
- Helps keep your spine aligned
- 5-year guarantee
£359
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MattressNextDay Ortho Support Foam Mattress
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Mattress details
Mattress
MattressNextDay Ortho Support Foam Mattress
Size
Firmness
Extra Firm
Construction
Foam
Rolled
Orthopaedic
Depth (cm)
20
Layers
2
Layer Details
Knitted Cover
A soft knitted cover that's breathable, which means heat can escape rather than build up around you. It helps keep you at an even temperature all night.
Reflex Foam
Reflex foam is a dense, responsive foam that conforms to the shape of your body. It offers tailored support to help improve your spinal alignment and posture.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- Proper space for two: At 75cm each for two people sharing, you can change position without negotiating for territory, which matters on a firm surface where you settle into your own spot.
- Length for taller sleepers: The 200cm length is 10cm more than the UK double, so anyone approaching six foot keeps their feet on the mattress rather than the footboard.
- Firm support across the full width: The dense reflex foam runs edge to edge, which means the extra firm feel is consistent whether you sleep in the middle or near the side.
- Suits different schedules: With 15cm more width than a UK double, a partner slipping out hours before you has less chance of disturbing your half of the bed.
- A firm bed for heavier builds, sized to share: Across owner feedback it's described as well suited to heavier builds, and the UK king lets two heavier sleepers share without crowding each other.
This size suits you if...
You share the bed every night and the UK double has started to feel cramped, one of you is over six foot and needs the 200cm length, or you're both after an extra firm surface with enough width that neither of you ends up perched near the edge. It also suits couples on different schedules who want early starts to go unnoticed.
Consider another size if...
You sleep alone, or your bedroom falls short of our suggested 2.7m x 2.9m minimum for a UK king. We'd recommend the UK double instead, which needs at least 2.6m x 2.8m and still gives 67.5cm each for two sharing.
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FAQ's
How big is the MattressNextDay Ortho Support Foam Mattress in a UK king?
The UK king measures 150 x 200cm, which is 5ft x 6ft 6in. That's the standard UK king footprint, so ordinary king sheets and a 230 x 220cm king duvet will fit. It's 15cm wider and 10cm longer than the UK double version of the same mattress.
Is the UK king Ortho Support mattress big enough for a couple?
Yes, comfortably for most. Two people sharing get 75cm of width each, and the dense reflex foam gives the same extra firm support across the whole surface. If you both want serious sprawling room, the UK super king gives 90cm each, though it needs a room of at least 3m x 2.9m.
Should I choose this mattress in a UK king or a UK double?
The UK king is 15cm wider and 10cm longer than the UK double, and gives each sharer 7.5cm more width. On an extra firm mattress like this, that extra space is useful because you don't sink towards each other; you each hold your own patch. Solo sleepers or smaller rooms are better served by the UK double.
What room size do I need for this mattress in a UK king?
We suggest a room of at least 2.7m x 2.9m for a UK king, which leaves space to walk round the bed and open drawers. Measure with wardrobes and bedside tables in place: a new build master bedroom can shrink quickly once the furniture is in. If it's tight, we suggest at least 2.6m x 2.8m for the UK double.
Is the UK king long enough for someone over six foot?
At 200cm, the UK king is one of the longer standard UK sizes, 10cm longer than the UK single, small double and double. For a taller sleeper, that length is often the real reason to size up. The UK super king is the same length, so going wider again wouldn't gain you anything in that direction.