Twin XL

Twin XL mattresses measure 38 inches wide by 80 inches long, which is the same width as a standard twin but five inches longer. That extra length is exactly why the size shows up so often in dorm rooms and guest rooms built with taller occupants in mind, even though it is still one of the narrower mattress sizes available.

For a tall adult, 80 inches of length is often the minimum needed to avoid feet hanging off the end of the bed, which is why twin XL is a common recommendation for single sleepers over six feet who do not need the extra width of a queen or king. It is also the standard length used in adjustable bed bases and daybeds marketed for taller users.

The narrow 38 inch width is the tradeoff, since it leaves little room to move around compared to a full or queen. Anyone sharing the bed, or anyone who shifts position a lot at night, usually outgrows the width well before the length becomes a problem. Twin XL sheets and comforters are sized specifically for this mattress and will not stretch to fit a standard twin or a queen.