Standard pillowcases measure 20 to 21 inches by 30 by 32 inches. Since a queen size pillow measures 20 inches by 30 inches, these pillows can typically fit comfortably in a standard size pillowcase. However, the pillow may be a tight fit if it’s unusually thick. In this case, it may be helpful to opt for a king size pillowcase since queen pillowcases are not readily available.