ROT13 / Caesar Cipher

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›What's ROT13?

Caesar cipher with a shift of 13. Because the English alphabet has 26 letters, applying ROT13 twice gives back the original — you don't need separate encode/decode.

›Is ROT13 secure?

Not at all — it's a 2,000-year-old cipher with 25 possible shifts. Use it only for spoiler tags or trivial obfuscation, never for security.

›Can I use a different shift?

Yes — pick any number from 1 to 25. ROT13 is just shift=13.

›Are uppercase and lowercase preserved?

Yes — case is preserved through the shift. Numbers and punctuation pass through unchanged.

›Is the tool free?

Yes — fully free, no signup.