ROT13 / Caesar Cipher
Apply a Caesar shift to text. ROT13 is the famous self-inverse version. Useful for puzzles, spoilers, light obfuscation.
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How to use ROT13 / Caesar Cipher
- Paste your text.
- Set the shift value (or click ROT13 for the classic 13).
- Copy the result.
What is ROT13 / Caesar Cipher?
The Caesar cipher is one of the oldest known ciphers, dating to Julius Caesar's correspondence. It shifts each letter forward or backward by a fixed amount in the alphabet. ROT13 — a shift of 13 — is self-inverse and widely used to hide minor spoilers in online discussions.
This is not real encryption. Don't use it for anything sensitive.
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FAQ
- Why is ROT13 special?
- Applying ROT13 twice returns the original text — it's self-inverse — so the same tool both encodes and decodes.
- Is this real encryption?
- No. Caesar ciphers are trivially reversible and meant for puzzles, spoilers, or light obfuscation — never for protecting sensitive data.
- Does my text get sent to a server?
- No — all shifting is done locally in your browser. Your text never leaves your device.