A double bed is a standard size mattress that measures 54 inches wide and 75 inches long, making it an ideal choice for couples who want to snuggle up together at night. When compared to other common bed sizes, the double bed falls between the single and king sizes in terms of width, while being shorter than the queen and king sizes. In contrast, a twin bed is narrower and shorter, making it better suited for smaller rooms or as a guest room. Ultimately, choosing the right bed size depends on personal preference and the layout of your bedroom.