Twin XL mattresses measure 38" x 80", providing the same length as Queen and King mattresses in a space-saving single sleeper width. With 5 extra inches of length compared to standard Twin mattresses, Twin XL sizes accommodate sleepers up to 6'7" tall and work perfectly with adjustable bed bases. The most popular mattress size for college dorm rooms, Twin XL beds are also ideal for taller teenagers, single adults in small apartments, and guest rooms. Browse our entire selection of Twin XL-sized mattresses below.