ROT13
Classic ROT13 letter rotation, self-inverse cipher for casual obfuscation.
CipherClassicClient-sideFree to use
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Try ROT13 with These Examples
Click on any example below to load it into the tool and see how ROT13 encoding works:
How to use
- Paste your text. Any English text.
- Click Transform. Same button encodes and decodes.
Common use cases
- Hiding spoilers in text
- Casual obfuscation
- Learning classical ciphers
Frequently asked questions
- What is ROT13 best used for?
- ROT13 is the internet standard for hiding spoilers, puzzle answers, and mildly sensitive text in plain-text forums and mailing lists. It provides just enough obfuscation that someone scrolling quickly will not accidentally read the answer, while making it trivial for an interested reader to reveal it with one click.
- Why is ROT13 self-inverse?
- The alphabet has 26 letters, and ROT13 shifts each letter by exactly half that, 13 positions. Shifting by 13 twice totals a shift of 26, which is a full cycle back to the original letter. This means you can use the exact same operation to both encode and decode, with no need to specify a direction.
- Does this tool send my text to a server?
- No. The transformation runs entirely in your browser using JavaScript. Nothing is transmitted to any server.
- Does ROT13 provide any real security?
- No. ROT13 offers no meaningful protection against anyone who wants to read your text. Any person who knows the name "ROT13" can decode it instantly, and automated tools can break it in microseconds. It is strictly for social conventions like spoiler tags, not for protecting sensitive information.
- What characters does ROT13 affect?
- Only the 26 standard Latin letters (a-z and A-Z) are rotated. Digits, punctuation, spaces, and all non-ASCII characters pass through unchanged. Case is preserved: uppercase letters stay uppercase and lowercase stay lowercase.
Related tools
How to use
- Paste your text. Any English text.
- Click Transform. Same button encodes and decodes.
Common use cases
- Hiding spoilers in text
- Casual obfuscation
- Learning classical ciphers
Frequently asked questions
- What is ROT13 best used for?
- ROT13 is the internet standard for hiding spoilers, puzzle answers, and mildly sensitive text in plain-text forums and mailing lists. It provides just enough obfuscation that someone scrolling quickly will not accidentally read the answer, while making it trivial for an interested reader to reveal it with one click.
- Why is ROT13 self-inverse?
- The alphabet has 26 letters, and ROT13 shifts each letter by exactly half that, 13 positions. Shifting by 13 twice totals a shift of 26, which is a full cycle back to the original letter. This means you can use the exact same operation to both encode and decode, with no need to specify a direction.
- Does this tool send my text to a server?
- No. The transformation runs entirely in your browser using JavaScript. Nothing is transmitted to any server.
- Does ROT13 provide any real security?
- No. ROT13 offers no meaningful protection against anyone who wants to read your text. Any person who knows the name "ROT13" can decode it instantly, and automated tools can break it in microseconds. It is strictly for social conventions like spoiler tags, not for protecting sensitive information.
- What characters does ROT13 affect?
- Only the 26 standard Latin letters (a-z and A-Z) are rotated. Digits, punctuation, spaces, and all non-ASCII characters pass through unchanged. Case is preserved: uppercase letters stay uppercase and lowercase stay lowercase.