Encode and decode with a letter shift
The Caesar cipher shifts every letter a fixed number of places along the alphabet — the oldest trick in cryptography, named after Julius Caesar. ROT13 is the popular shift-by-thirteen version used to hide spoilers and puzzle answers. This tool applies any shift to encode or decode text, which is perfect for learning how ciphers work or for light, playful obfuscation.
How to use it
- Enter your text.
- Choose the shift amount, or pick ROT13.
- Encode or decode, and copy the result.
Where it's used
- Hiding spoilers or puzzle answers with ROT13.
- Teaching the basics of substitution ciphers.
- Light-hearted puzzles and games.
Questions people ask
Is this secure? Not at all — there are only a handful of possible shifts, so anyone can crack it in moments. Use it for fun, never for protecting real secrets.
Is my text uploaded? No — the shift runs locally in your browser.