Measuring 38” in width and 80” in length, the Twin XL can be an awesome solution for adults with limited space in their bedrooms. Additionally, a Twin XL can be used for kids who have outgrown their Twin size mattress. You can put a Twin XL in guest rooms, kid’s rooms, and well pretty much anywhere. Now that you know the size mattress you prefer, shop below by Brand, Comfort Level, or Type to find the perfect mattress for you.