As its name suggests, an extra long twin mattress is a mattress that is as wide as a standard twin mattress but several inches longer. An extra long twin mattress is 39 inches wide and 80 inches long, while a standard twin mattress is 39 inches wide and 75 inches long.
The additional five inches of length provided by an extra long twin gives taller people more room to stretch out and sleep comfortably. While standard twin mattresses offer plenty of length for children and shorter adults, colleges and universities often use extra long twin beds in their dormitory rooms to accommodate taller teens and adults.
Because the width of an extra long twin is a slim 39 inches, which is the same as a standard twin's width, the mattress doesn't gobble up too much valuable space in a small bedroom or dormitory room, especially when you place it along a wall.
Because they are not as widely used as standard twin mattresses, some retailers consider extra long twin mattresses a specialty item. Therefore, they may be more difficult to find or may need to be special ordered. You must also purchase specially sized sheets, blankets and other bedding to get a proper fit, which may also be harder to find or may need to be specially ordered. However, there are online retailers who specialize in this size and offer many options. An additional drawback is that people with a hefty build may find the 39-inch width too narrow.