ROT13 Encoder/Decoder
Encode or decode ROT13 text instantly. Free online ROT13 cipher tool with real-time conversion.
Output will appear here...
What is ROT13 Encoder/Decoder?
ROT13 (Rotate by 13 places) is a simple 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 — encoding and decoding are the same operation. ROT13 is used for hiding spoilers, puzzle solutions, and offensive content, not for security.
How to Use
- Paste or type your text in the input area
- The ROT13 result appears instantly in the output panel
- Apply ROT13 again to the output to decode it back to the original
- Use Swap to reverse the direction and work back and forth
Examples
Encode text with ROT13
Decode ROT13 text
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Frequently Asked Questions
Is ROT13 secure?
No. ROT13 provides zero security. Anyone can decode it instantly. It is used only for obscuring text casually — hiding spoilers, jokes, or answers to puzzles. Never use ROT13 for sensitive data.
Does ROT13 affect numbers and punctuation?
No. ROT13 only rotates alphabetic characters (A-Z, a-z). Numbers, punctuation, spaces, and special characters remain unchanged.
Why is ROT13 called a Caesar cipher?
ROT13 is a specific case of the Caesar cipher with a shift of 13. The Caesar cipher was used by Julius Caesar to encode military messages. Any shift value (1-25) works, but ROT13 is special because encoding and decoding use the same operation.