A great bed size for your child’s first “big bed” that can last all the way through college. Good for small guest rooms, college dorm rooms, and more. The Twin XL (“XL” stands for extra long) is a popular and affordable space-saver for single sleepers too tall for a regular twin bed. 

With the width of a standard twin bed and the length of a queen bed, it combines space efficiency with enough legroom for taller sleepers to stretch out comfortably. 

Twin XL size bed dimensions: 38 inches 80 inches (96.5 centimeters by 203.5 centimeters). The twin XL size bed dimensions in feet  are 3.17 by 6.67.

This mattress size, like the twin mattress, is optimal for people who sleep like logs: straight up and down the length of the mattress without much horizontal sprawling, tossing or turning. If you're the sort of person who prefers to sprawl out, or who rolls around during the night, a twin XL will feel cramped (and you should consider a queen size mattress, or perhaps a king size). But if you don't think you'll need more than 3 feet of sleeping space, a Twin XL will work well for you.

The twin XL mattress can be a great mattress for couples, too: if you and your partner can't settle on a mattress firmness, you could purchase two twin XL mattresses and push them together. This space is equivalent to a king bed, and in fact this arrangement is called a "split king". 

Twin XL beds are incredibly versatile since they take up so little space, they can fit in many rooms. In general, any room size larger than 7 feet by 10 feet should work for one twin XL bed. If you'd like to fit in two twin XL beds (in an arrangement other than a bunk bed), you'll need comparable, or slightly greater, room than you would need to fit a king: a minimum of 10 feet by 12 feet for a split king or 13 by 13 foot for two separated twin XLs. In general, ensure you have at least two feet of walking space around your bed.

Be sure to use caution when purchasing a bed frame for your twin XL mattress. Many people mistakenly purchase a twin size bed frame, which is five inches too short. Depending on the style of frame, the twin XL mattress can hang off the end or simply not fit in the bed frame at all. Make sure to purchase a twin XL size bed frame or mattress foundation so the extra length you get from your twin XL won't be wasted!