Encode and Decode ROT13 Text Instantly
ROT13 replaces every letter with the one 13 places after it in the alphabet: A becomes N, B becomes O, and so on, wrapping around so that N becomes A again. Everything that is not an English letter — digits, punctuation, spaces, line breaks, accented characters, and emoji — passes through untouched. It runs entirely in your browser.
Why is there no separate decode button?
Because ROT13 undoes itself. The alphabet has 26 letters, so rotating by 13 twice moves
every letter a full 26 places and lands it back where it began. Encoding
Hello gives Uryyb, and encoding Uryyb gives
Hello. One operation, both directions — just paste whichever you have.
Is ROT13 secure?
Not remotely, and it was never meant to be. There is no key: anyone who recognises ROT13 can reverse it in seconds, and this page will do it instantly. Treat it as a way to hide text from a casual glance, not from anyone who is actually looking. If you need real protection, you need encryption, not a letter rotation.
For a rotation you can control the amount of, try the Caesar Cipher Tool — ROT13 is simply a Caesar cipher with the shift fixed at 13, which is the one shift that makes the cipher its own inverse.
What is ROT13 actually used for?
It became a convention on Usenet in the early 1980s for hiding spoilers, punchlines, and answers to puzzles, so that a reader had to make a deliberate choice to reveal them. That use survives on forums and in newsletters today. It also shows up in beginner programming exercises, in CTF and puzzle challenges as a first thing to try on scrambled-looking text, and occasionally in software to make a string non-obvious to someone skimming a configuration file.
What about numbers and other alphabets?
They are left exactly as they are. ROT13 is defined only over the 26 English letters, so
abc123xyz becomes nop123klm with the digits intact, and
café 中文 becomes pnsé 中文 — the accented
é and the Chinese characters do not move. A variant called ROT47 rotates
printable ASCII including digits and symbols, but that is a different scheme and is not
what this tool does. To scramble numbers too, look at the
A1Z26 Cipher or
Base64 Encode & Decode instead.
Last reviewed: August 2026