Last seen for £309 at Mattress Man on 10th November 2026
Arthur Sleep Cool Gel King Size Mattress
The Arthur Sleep Cool Gel Mattress is a hybrid, meaning it combines springs with foam layers, available in five UK sizes from Single up to Super King.
- Medium feel for most sleepers
- Gel-infused foam for cooler nights
- Targeted pocket-sprung support
Save with the previous model
Some retailers still sell the earlier version of this mattress for less than the current model's best price.
More available sizes
Last seen for £309 at Mattress Man on 10th November 2026
Last seen for £205 at Mattress Man on 4th November 2026
Mattress details
Mattress
Arthur Sleep Cool Gel Mattress
Size
Firmness
Medium
Construction
Pocket Spring
Hybrid
Gel
Depth (cm)
Layers
Layer Details
Key benefits
- 75cm each for two sharing: Each of you gets 75cm of width, which means you can change position at night without brushing against your partner every time.
- Extra length for taller sleepers: At 200cm long, the UK king is 10cm longer than the UK double, a real difference for anyone approaching six foot.
- Less partner disturbance from a hybrid: Springs with foam layers on top generally transfer less movement than a traditional open coil bed, and the extra width of a UK king adds distance too.
- Affordable route to a bigger bed: Upgrading to a UK king often means a price jump, but this mattress sits at the cheaper end of the market across all its sizes.
- Well liked by owners: Across verified owner reviews on Mattressman, it holds 4.8 out of 5 from 51 reviews, reassuring at this price point.
This size suits you if...
You share the bed every night and a double has started to feel cramped, especially if one of you is on a different schedule and gets up hours earlier. It's also the right call if either partner is approaching six foot, since the 200cm length gives feet somewhere to go, or if a dog has quietly become a permanent third occupant.
Consider another size if...
Your bedroom is under our suggested minimum of 2.7m x 2.9m for a UK king. In that case we'd recommend the UK double instead, which needs around 2.6m x 2.8m and is 15cm narrower.
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FAQ's
How big is the Arthur Sleep Cool Gel Mattress in a UK king?
It measures 150 x 200cm, which is 5ft x 6ft 6in. For two people sharing, that works out at 75cm of width each, noticeably more personal space than a UK double offers, plus extra length that taller sleepers tend to appreciate.
Is the UK king Arthur Sleep Cool Gel good for couples?
It's a sensible fit. The 75cm of width per person means fewer accidental nudges, and the hybrid construction, springs under foam, tends to soften movement across the bed. Arthur Sleep doesn't publish detailed construction specs, so if motion isolation is critical for you, judge it on feel rather than a spec sheet.
What room size do I need for a king size Arthur Sleep mattress?
We suggest a room of at least 2.7m x 2.9m, with 3.2m x 3.2m feeling genuinely comfortable. That allows walking space on both sides and room for wardrobes. This is our guidance rather than the manufacturer's, so measure your own room before committing.
Should I get the Arthur Sleep Cool Gel in a king or a super king?
The UK super king is 30cm wider than the UK king and the same length, but it needs a room of at least 3m x 2.9m by our guidance. For most couples the UK king is the sweet spot: a clear step up from a double without dominating the bedroom.
Is the king size worth it if my partner is over six foot?
Yes, and length is the real reason. The UK king is 10cm longer than the UK double at 200cm, which stops feet hanging off the end for anyone around the six foot mark. The extra 15cm of width helps too, but for tall sleepers the length is the upgrade that matters.