A: A Twin "extra long" is known most commonly as a Twin "XL". The "XL" stands for extra long. The dimensions of a extra long twin beds are 39 inches wide by 80 inches long. read more
An extra-long, fitted twin sheet -- the sheet that must fit the mattress -- measures 39-by-80 inches, 5 inches longer than a standard twin sheet; an extra-long twin flat sheet measures 66-by-102 inches. read more