When I look for a new bed, the sheer variety of sizes can be quite a puzzle. In the UK, two of the most popular choices for varying room sizes are the small double and the king size (often referred to by its metric dimensions of 150x200cm). Understanding the difference between these is vital, as using the wrong mattress on a frame can lead to poor support and a very uncomfortable night.

The Versatile UK Small Double

A standard UK small double mattress, also known as a "Queen" or "Three-Quarter" bed, measures 120cm wide by 190cm long ($120 \times 190 \text cm$). This translates to roughly 4 feet wide and 6 feet 3 inches long.

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Best for Solo Sleepers: I find this size is the "sweet spot" for individuals who want more room than a single bed but have a smaller bedroom. It offers an extra 30cm of width compared to a standard single.

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Space Saving: It is a lifesaver for guest rooms or studio apartments. It allows two adults to share the bed at a pinch, though it will feel quite snug.

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Teenage Bedrooms: It is an excellent upgrade for growing teenagers who need more space but cannot fit a full double in their room.

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The Luxurious 150x200cm King Size

The 150x200cm size is the standard for a UK king size bed. At 5 feet wide and 6 feet 6 inches long, it is significantly larger than the small double.

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Extra Length: One of the biggest advantages is the length. At 200cm ($2\text m$), it is 10cm longer than a small double or standard double. If you are over 6 feet tall, this extra legroom is essential to prevent your feet from hanging off the edge.

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Couple Comfort: This is the preferred choice for couples. It provides enough width for 150x200 bed size two people to sleep without disturbing each other, offering 15cm more width than a standard double.

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Room Requirements: Because of its footprint, I recommend ensuring your bedroom has at least 76cm of clearance on three sides to allow for easy movement and furniture access.

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Comparison and Compatibility

It is important to note that these two sizes are not interchangeable. A small double mattress will be 30cm too narrow and 10cm too short for a 150x200cm king size frame. Conversely, a king size mattress will hang over the edges of a small double base, which can damage the mattress structure and void your warranty.

Feature Small Double King Size (150x200 bed size)

Width 120cm (4'0") 150cm (5'0")

Length 190cm (6'3") 200cm (6'6")

Best For Solo sleepers, guest rooms Couples, taller individuals

Choosing between a UK small double and a 150x200cm king size bed depends entirely on your available floor space and sleeping habits. If you are furnishing a compact spare room or sleep alone, the small double is a practical, cozy choice. However, if you have the space and want to prioritise a restful, undisturbed night—especially if you are tall—the king size is a worthy investment in your well-being. Always double-check your frame measurements before purchasing to ensure a perfect fit.

Would you like me to help you find some highly-rated mattresses in either of these sizes that fit your budget in Singapore Dollars?