ROT13 Encoder and Decoder
Encode or decode text with ROT13, ROT5, ROT18 or ROT47. The same step does both directions, runs live in your browser and needs no sign-up or upload.
How to use ROT13
- 1Paste or type the text you want to scramble or unscramble.
- 2Choose ROT13 for letters, ROT5 for digits, ROT18 for both, or ROT47 for every printable character.
- 3Copy the result. To reverse it, paste the result back in with the same setting.
What makes it better
- ROT13, ROT5, ROT18 and ROT47 in one tool
- Symmetric: the same operation encodes and decodes
- Live output as you type, with emoji and non-Latin text left untouched
- Handles very large pastes without freezing the page
About ROT13
ROT13 swaps each letter for the one 13 places away, so A becomes N and N becomes A. Because the English alphabet has 26 letters, doing it twice gives back your original text, which means the same button both encodes and decodes. The page also offers ROT5 for digits, ROT18 for letters plus digits and ROT47 for all printable ASCII characters, all computed in your browser.
Common uses
- Hide a spoiler, punchline or puzzle answer so readers have to choose to decode it.
- Decode a ROT13 string found in a forum post, an old Usenet archive or a geocache hint.
- Obscure an email address from simple scrapers on a web page.
- Practice with ROT47 on a capture-the-flag challenge.
Example
Input
Hello, World!
Result
Uryyb, Jbeyq!
Good to know
- Classical ciphers offer no real security: a computer breaks them in milliseconds. For real encryption use AES-256 (see AES Encrypt).
- ROT13 only changes letters and ROT5 only digits. ROT18 combines the two, and ROT47 rotates every character from ! to ~, which is why it also scrambles punctuation.
- Because the operation is its own inverse, running it twice is a no-op. Do not expect it to hide anything from someone who recognizes it.
ROT13 FAQ
What is ROT13?
ROT13 is a letter substitution that replaces each letter with the letter 13 places after it in the alphabet. It is a special case of the Caesar cipher and was popular on early internet forums for hiding spoilers.
How do I decode ROT13?
Apply ROT13 again. Shifting by 13 twice moves a letter by 26, which is a full lap of the alphabet, so the original text returns. There is no separate decode mode.
What is the difference between ROT13, ROT5, ROT18 and ROT47?
ROT13 rotates the 26 letters, ROT5 rotates the ten digits by 5, ROT18 does both at once, and ROT47 rotates the 94 printable ASCII characters from ! to ~ by 47. Each of them is its own inverse.
Is ROT13 encryption?
Not in any useful sense. It has no key, so anyone can reverse it instantly. It is used for light obfuscation such as spoilers, never to protect secrets.