Free ROT13 Encoder & Decoder Online - Obfuscate Text Easily - Tooliz.online
Encode and decode text using the ROT13 substitution cipher instantly. Perfect for hiding spoilers, punchlines, or obfuscating email addresses on forums and websites.
Free ROT13 Encoder & Decoder Online - Obfuscate Text Easily - Tooliz.online
The Simple and Self-Inverse ROT13 Encoder/Decoder
ROT13 (short for "Rotate by 13 places") is a classic, simple letter substitution cipher and a specific case of the Caesar cipher. It works by replacing a letter with the letter 13 positions after it in the English alphabet, wrapping from Z back to A as needed.
Due to the 26 letters in the English alphabet, a rotation of 13 is exactly half. This means ROT13 is its own inverse: applying the ROT13 function twice will return the original plain text. This makes the tool incredibly convenient, as a single process handles both encoding (scrambling) and decoding (unscrambling).
Common Use Cases for ROT13:
- Hiding Spoilers and Punchlines: The primary use on online forums (like Usenet) is to prevent readers from accidentally seeing content like movie spoilers, puzzle answers, or the punchline of a joke before they choose to.
- Email Obfuscation: It is often used to lightly obscure an email address in website source code to defeat basic, non-sophisticated email harvesting bots, while keeping the address human-readable for conscious decoding.
- Simple Text Games: Used for educational purposes to demonstrate the basic principles of cryptography and substitution ciphers.
How ROT13 Works:
The conversion is applied only to the English alphabet (A-Z and a-z). All other characters—including numbers, punctuation, symbols, and spaces—are left untouched.
| Input (Plaintext) | A B C ... M | N O P ... Z |
| :--- | :--- | :--- |
| **Output (ROT13)** | N O P ... Z | A B C ... M |
Use our free tool to instantly encode or decode your messages entirely in your browser.
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