ROT13 Encoder / Decoder
Encode or decode text with the ROT13 cipher. ROT13 is its own inverse — applying it twice returns the original text. Conversion happens live as you type.
How it works: ROT13 rotates each letter by 13 positions in the alphabet. A→N, B→O, … Z→M. Non-letter characters (numbers, punctuation, spaces) are unchanged. Encoding and decoding are identical operations.
Input: 0 chars
Output: 0 chars
About ROT13 Encoder / Decoder
ROT13 (Rotate by 13) is a simple letter substitution cipher that replaces each letter with the letter 13 positions after it in the Latin alphabet. Because there are 26 letters, applying ROT13 twice returns the original text — making encode and decode the same operation.
Common Uses
ROT13 is commonly used to obscure spoilers in forums, hide puzzle answers, and obfuscate offensive content in Usenet posts. It is not a security cipher — it provides no real protection and is trivially reversible.
Frequently Asked Questions
No. ROT13 provides no cryptographic security whatsoever. It is a simple obfuscation technique, not encryption. Anyone who sees ROT13-encoded text can decode it in seconds. For real encryption, use AES-256.
Because the alphabet has 26 letters, shifting by 13 positions twice returns to the start. ROT13(ROT13(x)) = x for all letters. This is a unique property of ROT13 among all ROT-n ciphers.
No. Only ASCII letters (A–Z and a–z) are rotated. Digits, spaces, punctuation, and all non-ASCII characters pass through unchanged.
Yes, case is preserved. Uppercase letters map to uppercase letters and lowercase to lowercase. 'A' becomes 'N', 'a' becomes 'n', 'Z' becomes 'M', etc.