The standard sizes for adult mattresses are twin, full, queen and king. A longer alternative to the standard king-size bed is the California king. Crib and toddler size mattresses are for use in children's beds.
A standard twin-size mattress, also known as a single mattress, is 38 inches wide by 75 inches long. This size mattress is appropriate for a single child or adult, but it may be too short for taller individuals. An alternative to the standard twin is the Twin XL, which measures 39 inches wide by 80 inches long. The full-size, or double, mattress was historically used for couples, but it is more commonly used for a single sleeper, as of 2015. This mattress measures 54 inches wide by 75 inches long.
The queen-size mattress is 60 inches wide and 80 inches long, and is the most popular-sized mattress sold. A standard king-size mattress, sometimes called an Eastern king, is 76 inches wide and 80 inches long. In some areas, another version of the king-sized mattress, called the California king, is available. This mattress measures 72 inches wide by 84 long.
Crib mattresses dimensions vary slightly and range between 27.625 to 28.625 inches wide and 51.75 to 53 inches long. Toddler bed mattresses are 27 inches wide by 52 inches long.