Text Tools
ROT13 & Caesar cipher.
Shift every letter forward by a set amount. Default to classic ROT13 (shift 13), or pick any shift from 1-25 for a general Caesar cipher.
Input
Output
Enter text, set a shift, then Encode or Decode.
Why ROT13 decodes itself
ROT13 shifts every letter 13 places through the alphabet — exactly half of 26. Shift once and you get ciphertext; shift that same result by 13 again and the letters land right back where they started. That's why running this tool twice on the same shift always returns your original text, and why ROT13 (unlike a general Caesar cipher) needs only one button for both directions. Numbers and punctuation are left untouched.