A small double bed and mattress is 4 feet wide, 6 feet 3 inches long (122 x 190 cm). This is 6 inches (15cm) narrower than a standard double mattress. 4'0 small double beds are the ideal choice for a smaller room. Browse our wide range of small double mattresses in memory foam, pocket spring and more by leading UK brands. If you require any information, please feel free to contact is on 01282 614323.