ROT13 ("rotate by 13") shifts each letter in the alphabet 13 positions forward. Because the English alphabet has 26 letters, applying ROT13 twice returns the original text. It is commonly used to hide spoilers in forum posts and to obfuscate text without true encryption.

Does my data leave my device?

No. The ROT13 transformation is pure JavaScript running entirely in your browser.

Does it work on mobile?

Yes. The tool works on any modern mobile browser. Text is transformed instantly on click.

ROT13 Cipher

Apply ROT13 substitution cipher — rotate letters by 13 positions. Applying it twice restores the original.

How to use

Paste your text into the input box.
Click "Apply ROT13" — the substituted output appears instantly.
To decode ROT13 text, paste the encoded text in the input and click Apply ROT13 again.

Related tools

Caesar Cipher — shift by any amount (1–25)
Atbash Cipher — mirror-alphabet substitution
Morse Code Translator — dots and dashes

More ways to use this tool

ROT13 Decoder — reverse ROT13 text online
ROT13 Encoder — encode text with ROT13
ROT13 Cipher Tool — instant letter rotation

Frequently Asked Questions

What is ROT13?: ROT13 ("rotate by 13") shifts each letter in the alphabet 13 positions forward. Because the English alphabet has 26 letters, applying ROT13 twice returns the original text. It is commonly used to hide spoilers in forum posts and to obfuscate text without true encryption.
Does my data leave my device?: No. The ROT13 transformation is pure JavaScript running entirely in your browser.
Does it work on mobile?: Yes. The tool works on any modern mobile browser. Text is transformed instantly on click.

Last updated: 2026-05-20 By jarvisbox