ROT13 / Caesar Cipher
17 toolsEncode or decode text with a Caesar cipher.
Runs in your browser — your files and text stay on your device
Encode or decode text with ROT13 or a Caesar cipher by choosing a shift. These are simple substitution ciphers, fun for puzzles but not secure, since anyone can reverse them. It runs in your browser.
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Shift13
Output
How to use this tool
- 1Type text and pick a shift amount (13 = classic ROT13).
- 2The ciphered text updates instantly.
- 3Running the same shift again on the output decodes it back (for ROT13 specifically).
Frequently asked questions
Is this secure encryption?
No — a Caesar cipher is trivially breakable and meant for fun/obfuscation, not real security.
Why does ROT13 decode itself?
Shifting by 13 twice returns to the original letter, since 13 + 13 = 26, a full alphabet rotation.