ROT13 encoder and decoder
ROT13 hides puzzle answers and spoilers in forums and chats. It is a puzzle cipher that protects nothing.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter text.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
For each letter index x from 0 to 25: result = (x + 13) mod 26. Since 13 + 13 = 26, the same step both encodes and decodes.
Example
Result: ROT13 result: Jul qvq gur puvpxra pebff gur ebnq?; Letters processed: 28.
Why did the chicken cross the road?
Jul qvq gur puvpxra pebff gur ebnq?
Limits and caveats
- This is a puzzle and teaching cipher that is easy to break, so never use it to protect passwords or sensitive data.
- Only Latin letters A to Z change; Arabic letters, digits and symbols stay as they are.
Questions about this tool
How do I decode ROT13?
Paste it into the same tool. Applying ROT13 a second time returns the original text.
Does ROT13 change numbers?
No, only Latin letters change. To rotate digits and symbols as well, use ROT47.
How is ROT13 related to the Caesar cipher?
ROT13 is simply a Caesar cipher with a shift of 13.