In order from smallest to largest, the five standard mattress sizes are twin, full, queen, king and California king. Twin mattresses are 38 inches wide by 75 inches long, full 53 inches by 75 inches, queen 60 inches by 80 inches, king 76 inches by 80 inches and the California king 72 inches by 84 inches.
Some companies additionally produce an XL twin mattress that is a few inches longer than the standard. Twin mattresses are also known as single mattresses. A full-sized mattress, also called a double, is actually meant for a single person shorter than 5 feet 5 inches tall, according to the Better Sleep Council. In fact, both the twin and the double are typically too short for most adults, especially men. If a couple sleeps on a double mattress, each person has only as much sleeping space as a crib provides.
A standard king provides approximately the same amount of width for two people as two twin beds. Similarly, two XL twins pushed together is almost exactly the same as a standard king. The California king is similar in size to the king, except it is four inches narrower and four inches longer.
Mattresses are also sized for cribs and for toddlers.