Polybius Square Cipher

Substitute each letter with its row + column digits on a 5×5 grid.

Keyword (optional) Preset Encrypt Decrypt

Text

Output

5×5 key grid (I/J merged):

 A    B    C    D    E 
 F    G    H   I/J   K 
 L    M    N    O    P 
 Q    R    S    T    U 
 V    W    X    Y    Z

About this tool

Decimal coordinates from a Polybius square encode each letter (I/J merged). An optional keyword seeds the grid for a key-dependent encoding.