Dormeo Octasmart Premium King Size Mattress
The Dormeo Octasmart Premium is a 17cm foam mattress built around Dormeo's Octaspring foam springs, which means you get some of the springiness of a traditional mattress without any metal coils.
- Firmer at hips, softer at shoulders
- Removable anti-allergenic cover
- 200-night trial & 18-year guarantee
£419
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Dormeo Octasmart Premium Mattress
More available sizes
Mattress details
Mattress
Dormeo Octasmart Premium Mattress
Size
Firmness
Medium Firm
Construction
Foam
Pocket Spring
Depth (cm)
17
Layers
4
Layer Details
Smart performance cover
An anti-allergenic, removable cover with comfort pockets. Being removable means you can take it off for cleaning, which is handy if you suffer with allergies.
Aerocell top layer
A layer of Aerocell foam sits directly beneath the cover. This is the comfort layer you settle into when you first lie down.
9cm Octaspring core
Foam springs arranged in 5 zones, which means different areas of the mattress respond differently to your body. You should feel firmer support under heavier areas like the hips and a gentler give at the shoulders.
Ecocell base
An Ecocell foam base anchors the mattress. It provides the stable foundation the spring layer works against.
Layer details from dormeo.co.uk product page, September 2026.
Key benefits
- 75cm each for couples: Two people sharing get 75cm of width apiece, which means fewer accidental elbows and less need to synchronise turning over.
- Foam springs across a wider bed: The 9cm Octaspring core responds locally to each body, so a partner shifting position on their side of a 150cm mattress is less likely to wake you.
- Extra length for taller sleepers: At 200cm, the UK king is 10cm longer than the UK double, a difference anyone approaching six foot will feel at their feet.
- Five zones, two sleepers: The zoned core gives firmer support under the hips and softer give at the shoulders for each of you, whatever mix of positions you sleep in.
- A slim 17cm profile: Yes, it is shallower than many hybrids, but a lighter, slimmer mattress is easier to turn and make up on a wide king frame.
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 the other feels every exit. It also suits taller sleepers, since the 200cm length gives anyone around six foot proper foot room. If pregnancy or recovery has you propping pillows and shifting position through the night, the extra width stops that spreading into your partner's space.
Consider another size if...
Your bedroom falls short of the 2.7m x 2.9m we suggest as a minimum for a UK king. In that case we'd recommend the UK double instead, which needs at least 2.6m x 2.8m by our guidance.
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FAQ's
How much space does each person get on a UK king Octasmart Premium?
Two people sharing get 75cm of width each. That is 15cm more total width than the UK double, which sounds modest but changes how the bed feels night to night: you can turn over, stretch out or prop yourself on pillows without crossing into your partner's half.
Is the Dormeo Octasmart Premium UK king long enough for tall sleepers?
At 200cm, or 6ft 6in, it is 10cm longer than the UK double, and for many buyers that length matters more than the width. If one of you is approaching six foot and currently sleeps with feet at the edge of the mattress, the UK king solves that.
What room size do I need for the Octasmart Premium in a UK king?
We suggest at least 2.7m x 2.9m, with 3.2m x 3.2m feeling comfortable. That is our own guidance, not Dormeo's, and it assumes you want to open drawers and walk round both sides. Measure with wardrobes in mind: a new build master can feel smaller than the floor plan suggests.
Does the UK king help if my partner gets up earlier than me?
It helps in two ways. The 150cm width means their side of the bed is genuinely their side, and the Octaspring foam core responds where weight is applied rather than bouncing the whole surface. You may still notice a partner leaving, but far less than on a narrower mattress.
Where can I buy the Octasmart Premium in a UK king?
Compare the retailers listed on this page. The prices shown here are updated as retailers change them, so you are seeing current figures rather than a snapshot, and it is worth checking back if you are not ready to buy today.