Polybius CalculatorThis page defines Polybius coding. The Polybius cipher has been used for centuries, and is derived from a grid. If you have plain text, then select the plain text option, otherwise if you have a Polybius code, then select the option on the radiobutton: 1 2 3 4 5 1 A B C D E 2 F G H I/J K 3 L M N O P 4 Q R S T U 5 V W X Y Z |