What is the size of a full-size mattress?

A full-size mattress, also known as a double mattress, measures 53 inches wide and approximately 75 inches long. This is the same length as a twin-size mattress.

A full-size bed is recommended for a single sleeper who is no more than five feet and five inches tall as it leaves only about 27 inches of sleeping space, the same space as that of a crib mattress.

As of 2014, full-size beds are increasingly popular with parents, who often choose them over twin-size beds. The extra space is useful for parents to sit on during children's reading and tuck-in times. Full-size beds are often used in smaller guest rooms as well.