Question: what is the size of a double bed mattress?
Answer: What size is a double bed and mattress? A standard double bed and mattress is 135cm wide and 190cm. In imperial dimensions, this is equal to 4 feet 6 inches wide and 6 feet 3 inches long. As the most common size for a bed and mattress, they're ideal for two people, especially when bedroom space is at a premium.