A king size mattress is a popular choice for couples who want more room than a double bed, but don’t need as much space as a super king. A king size mattress measures 150 x 200 cm (5’ x 6’6"), which gives each person an extra 15 cm (6") of width compared to a double bed. A king size mattress can fit in most standard bedrooms and can provide more comfort and support for your back and joints. British Bed Store offers a variety of king size mattresses in different types and qualities, from latex to orthopaedic. You can also find matching headboards and bed frames to complete your bedroom look.