What size is a UK king-size mattress?

A UK king-size mattress is 5ft (150cm) wide by 6ft 6in (200cm) long. Each sleeper gets 75cm of width, 15cm more than a double. The length is the same as a super king. UK king is narrower than a US king (193cm) and not interchangeable, so do not use an imported mattress with a UK-bought frame.

How heavy is a king-size mattress?

Pocket sprung models weigh 30 to 50kg. Hybrid memory foam and latex run 40 to 60kg. Two-person lift is the standard for delivery and for turning. Roll-packed (bed-in-a-box) versions are easier to move into the house, but weigh the same once expanded.

How long does a king-size mattress last?

The Sleep Council recommends replacing a mattress every 7 to 8 years. Mid-market pocket sprung tends to hit that. Premium brands with hand-tufted construction (Hypnos, Vispring) often run 10 years or longer. Memory foam without a spring layer can sag earlier under heavier sleepers.

How thick should a king-size mattress be?

22 to 30cm covers most of the market. Below 22cm you are usually looking at a topper or a guest mattress. Pocket sprung and hybrid models need at least 25cm to fit the spring layer plus comfort fillings. Check headboard clearance before ordering anything over 28cm. The mattress can sit above the rail.

Will a king-size mattress fit through a standard UK door?

A standard internal door is 76cm wide. A 150cm-wide king-size mattress goes through on its side with room to spare. The pinch point is the stair turn, especially in older terraced houses with a quarter landing. Roll-packed bed-in-a-box mattresses solve this. They arrive in a 50cm by 50cm box.

Find the latest deals all in one place
Prices updated daily
Search from over 650,000 products

RattanTree King-Size Mattresses

Updated 31 May 2026

5 RattanTree King-Size Mattresses from 13 UK Retailers in June ’26

(5 items found)

Sort By

Applied Filters

RattanTree Clear all filters

Filters Clear filters

Clear filters

Compare

Divan Base Bed Frame With Headboard - No Mattress No Storage King 150x200cm

£99.99

Compare

Memory Foam Mattress Soft Fabric Skin-friendly Mattress Breathable Cover 2 Layer For More Supportive 5ft King 150x200x30cm

£199.99

Compare

Memory Foam Mattress Soft Fabric Skin-friendly Mattress Breathable Cover 2 Layer For More Supportive 5ft King 150x200x25cm

£179.99

Compare

Memory Foam Mattress Soft Fabric Skin-friendly Mattress Breathable Cover 2 Layer For More Supportive 5ft King 150x200x15cm

£149.99

Compare

Memory Foam Mattress Soft Fabric Skin-friendly Mattress Breathable Cover 2 Layer For More Supportive 5ft King 150x200x20cm

£159.99

Page 1 of 1

Home Design & Furniture Styling Guides

Fitted Wardrobes Out of Reach? Off-the-Shelf Done Right

By Jason · 4 June 2026
Dining Table and Chairs Sets

By Jason · 31 May 2026
Dining Table Buying Guide

By Jason · 27 May 2026
How to Choose a Mattress

By Jason · 23 May 2026
Best Mattress UK

By Jason · 18 May 2026
Garden Lighting

By Jason · 13 May 2026

Shop With Confidence

1
Search
Search from over 650,000 products - all in one place
2
Compare
Side-by-side prices from leading UK furniture retailers
3
Buy
Click through to your chosen retailer and check out as normal
4
Love
Get your ideal furniture at a great price - and love your home

RattanTree King-Size Mattresses

5 RattanTree King-Size Mattresses from 13 UK Retailers in June ’26

Home Design & Furniture Styling Guides

Fitted Wardrobes Out of Reach? Off-the-Shelf Done Right

Dining Table and Chairs Sets

Dining Table Buying Guide

How to Choose a Mattress

Best Mattress UK

Garden Lighting

Great prices, trusted stores

Product Categories

Shop With Confidence

Buying Ideas & Help