Encoding
ROT13 encode or decode text
ROT13 shifts each ASCII letter of your text 13 places along the alphabet, the fixed Caesar cipher used to hide spoilers in forums and blur strings in shared config samples. Because 13 is half of 26, the same pass both encodes and decodes: paste a scrambled message like Gur dhvpx oebja sbk and it reads as plain English. Digits, punctuation, and accented characters stay exactly where they are.
How to use ROT13
- Open ROT13 in the Toolbox101 app.
- Paste the text to decode: for example
Gur dhvpx oebja sbk whzcf bire gur ynml qbt. - Read the shifted result in the
Outputbox, which updates as you type. - Click
Copyto take the decoded text elsewhere. - To re-scramble the message, paste the output back into the
Inputbox: ROT13 undoes itself on the second pass.
Worked example
ROT13 returns the output below for this input.
Input
The quick brown fox jumps over the lazy dogOutput
Gur dhvpx oebja sbk whzcf bire gur ynml qbtCheck it yourself: open ROT13 and enter the same input.
Frequently asked questions
What is ROT13 and why shift by 13?
ROT13 is a Caesar cipher with a fixed shift of 13: a becomes n, b becomes o, and so on around the 26-letter alphabet. Because 13 is exactly half of 26, applying it twice returns the original text, which is why one tool both encodes and decodes.
How do I decode ROT13 text?
Paste the scrambled text into the Input box and copy what the Output box shows. There is no encode/decode toggle because none is needed: the transformation is its own inverse, so the second pass restores the original. Numbers, punctuation, and whitespace pass through untouched.
Is ROT13 encryption or just obfuscation?
ROT13 is obfuscation, not encryption. It uses a fixed, keyless substitution that anyone can reverse by eye, and it adds no secrecy whatsoever. Use it for spoilers and hiding text from casual glances; for real protection, use an encryption algorithm with a secret key, such as AES.
What is the difference between ROT13 and ROT47?
ROT13 only shifts the 26 letters, leaving digits and punctuation alone. ROT47 instead rotates all 94 printable ASCII characters (letters, digits, and symbols) by 47 positions inside that range, so it scrambles a much wider set of text. Both are keyless and self-inverse.