A "twin size" mattress is a standard bed size that measures 38 inches wide by 75 inches long. It is commonly used for children's beds, guest rooms, and smaller spaces due to its compact dimensions. Twin size mattresses are often paired with twin size bed frames and bedding, making them a popular choice for those seeking a simple and space-efficient sleeping solution. In addition to the standard twin size, there is also a "twin XL" option, which is slightly longer at 80 inches. This makes the twin XL ideal for taller individuals or for use in college dorms, where space is limited but comfort is essential. Both sizes are widely available in various materials and styles, including memory foam, innerspring, and latex.