ROT13 Encoder / Decoder

What is ROT13?

ROT13 ("rotate by 13 places") is a simple letter substitution cipher that replaces each letter with the letter 13 positions after it in the alphabet. Because the English alphabet has 26 letters, applying ROT13 twice returns the original text — encoding and decoding are identical operations.

ROT13 Example

Hello, World! → Uryyb, Jbeyq!

Non-letter characters (spaces, digits, punctuation) are left unchanged by ROT13.

ROT47

ROT47 extends the concept to all printable ASCII characters (codes 33–126, which includes digits and common symbols). Each character is shifted by 47 positions within that range. Like ROT13, it is its own inverse.

Use Cases

• Hiding spoilers in online forums
• Obfuscating text without real security
• A fun puzzle for basic ciphers

Note: ROT13/ROT47 provides no cryptographic security. Do not use it for sensitive data.