ROT13 and ROT47 Cipher Converter

What is ROT13?

ROT13 replaces each Latin letter with the one 13 positions further along the alphabet, wrapping around at the end. This tool also offers three relatives: ROT5 rotates the decimal digits by 5, ROT18 combines ROT13 for letters with ROT5 for digits, and ROT47 rotates across the printable ASCII range.

Type your text, choose a variant, and the result comes back transformed.

Why 13 is the number

Because the Latin alphabet has 26 letters, and 13 is exactly half. Rotating by 13 twice returns you to the start, so encoding and decoding are the same operation and one function does both.

Every variant here shares that property. ROT5 works because there are 10 digits, and ROT47 because its character range has 94 positions. Applying any of them a second time restores the original text, which is why there is no separate decode mode.

Are there alternatives?

If the goal is hiding text from someone who might actually look, everything else. Authenticated Encryption is the real answer, with a key and a guarantee.

If the goal is making text unreadable at a glance, ROT13 is the traditional choice and Text Flipper is the more visual one. Base64 is also commonly mistaken for obfuscation and is no better at it.

Fun facts and more info

ROT13 is a Caesar cipher, the technique named for its use in Roman military correspondence, where any shift could be chosen. Fixing the shift at half the alphabet is the one refinement that makes it self-inverse.

It has a genuine niche: hiding spoilers, puzzle answers, and punchlines in plain text, where the point is that a reader must choose to decode rather than be unable to. Usenet convention made this standard, and it persists.

There is no confidentiality here whatsoever. A substitution cipher with a fixed, published shift protects nothing, so never use it for passwords or sensitive data.