Twin size mattresses comes in two different variations, twin and twin extra long. A regular twin mattress is 39 inches wide and 75 inches long.
A twin extra long is 39 inches wide and 80 inches long. This size is suitable for a toddler or child bed.
Full size mattresses are also available in two different variations. A regular full size mattress is 54 inches wide and 75 inches long.
A full extra long mattress measures 54 inches wide and 80 inches long. This size is commonly found in university or college dorm rooms.
A queen size mattress measures 60 inches wide by 80 inches long, and is a workable size for most master bedrooms. Queen size beds are often offered at hotels and motels.
King size mattresses are available in two different variations. A regular king size mattress measures 76 inches wide by 80 inches long.
A California, or Western, king mattress is 72 inches wide by 84 inches long.