There are five basic sizes of pillowcases, including pillowcases to fit standard, queen, king, Euro and travel pillows, measuring from 12 to 36 inches tall with widths from 16 to 36 inches. A standard pillowcase fits a standard pillow that measures 20 inches tall by 26 inches wide.
Queen pillowcases fit queen pillows measuring 20 inches tall by 30 inches wide, while a king pillow and its pillowcase measure 20 inches tall and 36 inches wide. A Euro-style pillow is 26 inches tall by 26 inches wide, while a standard travel pillow is 12 inches tall and 16 inches wide, with pillowcases sized accordingly. Most twin beds use one standard-size pillow, while full and queen use two. King-sized beds usually require two king-sized or three standard-sized pillows.