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ROT13 Encoder / Decoder
Encode or decode ROT13 text instantly. Because ROT13 is symmetric, the same operation encodes and decodes. Works offline.
ROT13 is its own inverse — applying it twice returns the original text.
ROT13 Encoder / Decoder
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 returns the original text — making it its own inverse.
How ROT13 works
- A → N, B → O, C → P … M → Z
- N → A, O → B … Z → M
- Numbers, punctuation, and spaces are unchanged.
Common uses
- Spoiler protection: hiding plot details in forums and social media.
- Puzzle obfuscation: concealing answers in riddles or quizzes.
- Email harvesting protection: some older tools used ROT13 on addresses.
- Joke encoding: widely used on Usenet and early internet communities.
Security note
ROT13 provides no real security. It is trivially reversible and should never be used to protect sensitive information. For actual encryption, use AES or other modern ciphers.