ROT13 / Caesar Cipher
Encode or decode text with ROT13 or any Caesar shift (1–25). Useful for spoiler protection and puzzles.
Quick answer: Encode or decode text with ROT13 or any Caesar shift (1–25). Useful for spoiler protection and puzzles.
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Frequently asked questions
- Is this real encryption?
- No — the Caesar cipher was broken about 2,000 years ago. Use it for puzzles, hiding spoilers in forum posts, and CTF challenges. For real privacy, use our Secure Note Encrypt/Decrypt tool, which uses AES-256.
- Why is ROT13 useful?
- ROT13 is its own inverse — encoding twice returns the original. It's the conventional way to hide plot spoilers, joke punchlines and mild profanity in plaintext forums and email.
- Does it preserve case?
- Yes — uppercase letters map to uppercase, lowercase to lowercase. Non-letters are passed through unchanged.
- Can I shift by negative amounts?
- There's no need — a left shift of 3 is the same as a right shift of 23. Use whichever direction matches the puzzle you're solving.
- Is my text uploaded?
- No — the substitution runs entirely in your browser.