About the ROT13 Encoder and Decoder
ROT13 shifts each letter 13 places through the alphabet, so A becomes N and N becomes A. Because 13 is half of 26, applying it twice returns the original text, which means one button both hides and reveals. It is a convention for lightly obscuring text that a reader should have to opt into seeing, such as spoilers, puzzle answers and joke punchlines on forums and in email.
Only the 26 English letters are rotated; digits, punctuation, spaces, accented letters and every non-Latin script pass through unchanged. That last point is the practical limit of the trick. A spoiler written in Greek, Cyrillic or with plenty of accents survives ROT13 largely legible, and word lengths stay intact either way, so a one-word answer is often guessable from its shape alone.
ROT13 provides no security whatsoever; it is a social convention, not encryption, and it shows up in Usenet archives, crossword answer keys and the occasional job advert as a mild "do not read this yet" marker. For an arbitrary shift, use the Caesar Cipher tool. For the variant that scrambles digits and punctuation too, use ROT47. When the text genuinely needs protecting rather than merely hiding, Encrypt and Decrypt is the tool to reach for.
How to use
- Paste the text.
- Read the rotated result. Run it again to reverse it.
- Copy the output.
Common questions
- How do I decode ROT13?
- Apply ROT13 again. The same operation encodes and decodes.
- Is ROT13 secure?
- No. It is a convention for hiding text from casual view, not encryption.
- Are numbers changed?
- No. Only letters A-Z and a-z are rotated. For numbers too, use ROT47.