Using the ROT13 / Caesar cipher encoder and decoder
Shift every letter through the alphabet by a fixed amount. The default shift of 13 is ROT13, which is its own inverse; set any shift from 0 to 25 in the settings. Everything runs in your browser – nothing you paste is uploaded or stored, so it is safe for tokens, keys and private data.
What is ROT13?
ROT13 is a Caesar cipher with a shift of 13. Because the Latin alphabet has 26 letters, applying it twice returns the original text, so the same operation both scrambles and unscrambles. It is used to hide spoilers and puzzle answers, not for security.
What is a Caesar cipher?
A Caesar cipher replaces each letter with one a fixed number of places further along the alphabet, wrapping round from Z to A. It offers no real protection – there are only 25 possible shifts to try – but it is a classic introduction to cryptography.
Are numbers and punctuation changed?
No. Only A–Z and a–z are shifted. Digits, spaces, punctuation and other characters pass through unchanged, and letter case is preserved.
What else can this tool do?
The same converter also handles base64, url, html entities, jwt, hex, binary and morse code. Pick a format from the menu without leaving the page.
Is any of this encryption?
No. Encoding changes how data is represented so it can travel safely through a channel; it does not protect it. Anyone can reverse Base64, percent-encoding, hex or ROT13. For a one-way fingerprint use the hash generator; to check JSON you have decoded, use the JSON formatter.