A double size mattress is a common choice for single sleepers who want more space, or for couples who don’t mind being close together. A double size mattress measures 135 x 190 cm (4’6" x 6’3"), which is the same length as a single bed but twice as wide. A double size mattress can fit in most small to medium-sized bedrooms and can provide enough comfort and support for most people. British Bed Store has a selection of double size mattresses in different options and prices, from gel to open coil. You can also browse through their collection of stylish bed frames and headboards to match your double size mattress.