Due to their larger surface area, full beds cost more than twin XL beds. While the twin XL is best for tall solo sleepers, a full is best for shorter sleepers or those who share the bed. 12 juin 2023 · Trouble sleeping? Answer these 5 easy questions to discover your perfect mattress Start Quiz The twin XL mattress dimensions (38 inches wide, 80 inches long) are best suited for single sleepers who are over 6 feet tall, or growing children and teens who may exceed 6 feet eventually.