Hiding a spoiler in a comment
Rotate the spoiler and post it. Anyone who wants to read it rotates it back; casual readers see gibberish.
Use ROT13 Encoder and Decoder
Converts text to rot13 in this tab, with nothing sent anywhere.
Runs entirely on your deviceThe conversion happens in this browser tab. Nothing you type is uploaded, logged or stored, which is worth knowing for anything you would not paste into a search box.
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Browse all developer and data toolsAbout ROT13 Encoder and Decoder
ROT13 is the simplest cipher still in everyday use, and its charm is that it is its own inverse: rotating each letter thirteen places forward through the alphabet, then doing it again, brings you back to the start, because thirteen plus thirteen is twenty-six, a full loop. This makes it perfect for its actual purpose, which was never security. ROT13 hides a spoiler, a punchline, a puzzle answer or a mild plot detail from someone reading casually, while letting anyone who wants to read it do so with a single click. It is obfuscation as a social convention rather than protection. This tool applies the rotation to letters and leaves everything else - numbers, punctuation, spaces - untouched, which is the standard behaviour.
Using ROT13 Encoder and Decoder
- Each letter is moved thirteen places forward through the alphabet, wrapping from Z back to A.
- The same operation reverses it, because applying ROT13 twice returns the original - thirteen forward twice is a full rotation of twenty-six.
- Case is preserved: an uppercase letter stays uppercase, a lowercase letter stays lowercase.
- Numbers, punctuation, spaces and any non-letter are left exactly as they are.
- There is no key and no setting, since ROT13 is a fixed rotation, which is why one button both encodes and decodes.
Where rot13 encoder and decoder helps
Sharing a puzzle answer
ROT13 lets an answer sit in plain sight without giving it away to someone glancing at the page.
Before you use the result
- ROT13 is not encryption and offers no security whatsoever. Anyone can reverse it instantly; it hides text only from casual reading.
- It only affects the 26 English letters. Accented letters, other alphabets, numbers and symbols pass through unchanged.
- Because it is a fixed rotation, there is nothing to configure - for an adjustable shift, use the Caesar cipher tool.
- Applying it to already-rotated text simply returns the original, which is the point.
- It is meant for hiding spoilers and puzzle answers, not for protecting anything of value.
Questions about ROT13 Encoder and Decoder
Is ROT13 secure?
Not at all. It is trivially reversible and offers no protection. It hides text from casual reading, nothing more.
Why does one button do both?
Because ROT13 is its own inverse. Applying it twice returns the original, so encoding and decoding are the same operation.
What happens to numbers and symbols?
They are left unchanged. Only the 26 English letters are rotated.
Can I change the shift?
Not here - ROT13 is fixed at thirteen. Use the Caesar cipher tool for any other amount.
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