Text Tools
Caesar Cipher (ROT13)
Encode or decode text with a Caesar shift cipher, including the popular ROT13.
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ROT13 is its own reverse: apply it again to decode. For other shifts, decode with a shift of 26 minus your value.
About the Caesar Cipher (ROT13)
A Caesar cipher shifts every letter along the alphabet by a fixed amount, wrapping around from Z back to A.
This tool lets you choose any shift from 0 to 25, with quick presets for ROT13 and the classic shift of three used by Julius Caesar.
ROT13 is a special case that is its own reverse, so applying it twice returns the original text, which makes it popular for hiding spoilers and puzzle answers.
Key features
- Any shift from 0 to 25
- One-click ROT13 and classic shift-of-three
- Live encode and decode
- Numbers and symbols pass through unchanged
How to use
- 1Type or paste your text.
- 2Choose a shift, or click ROT13 or Classic.
- 3Copy the encoded or decoded result.
Frequently asked questions
- How do I decode a Caesar cipher?
- Use the opposite shift. If it was encoded with a shift of n, decode with a shift of 26 minus n. ROT13 decodes with ROT13 again.
- Is a Caesar cipher secure?
- No. With only 25 possible shifts it is trivial to break, so it is best for puzzles, spoilers and learning, not real security.
- Is my text uploaded anywhere?
- No. Everything runs in your browser, so your text never leaves your device.