Encode or decode text using ROT13 or Caesar cipher with any shift value. ROT13 (shift of 13) is self-reversing - apply it twice to get the original text.
| Original | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
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| Encoded | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | A | B | C | D | E | F | G | H | I | J | K | L | M |
ROT13 is commonly used to hide spoilers, puzzle solutions, and offensive content online. It's not encryption - just a simple letter substitution that's easy to reverse.
Choose a cipher preset
Select ROT13 (13), ROT1, Caesar (3), or enter a custom shift value.
Enter your text
Type or paste the text you want to encode or decode.
Copy the result
View both encoded and decoded outputs, then copy whichever you need.
Yes, our ROT13 and Caesar cipher tool is completely free with no limitations. Encode and decode as much text as you need without sign-ups or restrictions.
Absolutely. All cipher operations happen entirely in your browser using JavaScript. Your text is never sent to any server. This ensures complete privacy for your encoded messages.
ROT13 (rotate by 13) is a simple letter substitution cipher that replaces each letter with the letter 13 positions after it in the alphabet. Since the alphabet has 26 letters, applying ROT13 twice returns the original text—it's self-reversing.
The Caesar cipher is named after Julius Caesar who used it in his correspondence. It shifts each letter by a fixed number of positions. ROT13 is a specific Caesar cipher with shift of 13. Caesar traditionally used a shift of 3.
No, ROT13 and Caesar ciphers provide no real security—they're trivially easy to break. They're used for light obfuscation like hiding spoilers, puzzle answers, or offensive content. For actual security, use proper encryption like AES.