FreeDev Tools

ROT13 Encoder / Decoder

Encode or decode text with the ROT13 substitution cipher

ROT13 Cheat Sheet

Plain:ABCDEFGHIJKLMNOPQRSTUVWXYZ
ROT13:NOPQRSTUVWXYZABCDEFGHIJKLM

ROT13 (Rotate by 13 places) is a simple letter substitution cipher that replaces each letter with the letter 13 positions after it in the alphabet. Because the English alphabet has 26 letters, applying ROT13 twice gives back the original text — it is its own inverse. ROT13 is commonly used on internet forums to hide spoilers, puzzle answers, and off-color jokes. It offers no real security but is a fun and instantly recognizable cipher.

Frequently Asked Questions

ROT13 (Rotate by 13) is a simple letter substitution cipher that replaces each letter with the letter 13 positions after it in the alphabet. A→N, B→O, etc.