ROT13 cipher

ROT13 ("rotate by 13 places") is a simple letter shift: each letter is replaced by the one 13 positions further in the alphabet. Because the alphabet has 26 letters, applying it twice returns the original text - so the same function both encodes and decodes. ROT13 has been used for decades to hide punchlines, spoilers or solutions so they are not read by accident.

You paste your text and get the ROT13 version; paste a ROT13 version and you get the plain text back. Only the letters A to Z (upper and lower case) are shifted - digits, spaces and punctuation stay unchanged, as do umlauts and other special characters. That keeps the structure of the text intact.

The whole conversion runs entirely locally in your browser in pure JavaScript - your text is not uploaded, not stored, and no foreign library is loaded from a CDN. ROT13 is obfuscation, NOT secure encryption - for real protection use the file encryption tool.

Specifications

In 3 steps

1. Paste the text into the text field.
2. Click convert (encodes and decodes alike).
3. Read the result or download it as a text file.

Limitations: ROT13 shifts only the Latin letters A to Z; all other characters (digits, punctuation, umlauts, emojis) stay unchanged. It is pure obfuscation without a key and provides NO security - anyone can reverse it with the same tool.

FAQ

Related tools

Unicode escape · Text to binary · Encrypt file · Extract password ZIP