How big is an XL twin-size bed?

Twin XL mattresses are 39 inches wide and 80 inches long. They are five inches longer than standard twin-sized beds and are the same length as both king- and queen-sized beds.

Both twin and twin XL beds can only accommodate one sleeper comfortably, but the extra five inches in length of the twin XL provide more comfort for adults and teenagers. A twin XL may be suitable for a guest room because it does not take up much space, but is still size appropriate for taller adults. Two twin XL beds next to each other equal the size of one king-sized mattress. Extra-long twin mattresses are also the most common mattress size found in college dorm rooms.