ROT13 Encoder / Decoder
Your data never leaves your browserApply ROT13 substitution cipher — encodes and decodes in one step.
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About ROT13 Encoder / Decoder
ROT13 is a simple letter substitution cipher that rotates each letter 13 positions in the alphabet. Since the alphabet has 26 letters, applying ROT13 twice returns the original text — making the same operation both encode and decode. Non-letter characters are left unchanged.
How to use
- Paste or type your text into the input panel.
- The ROT13 result appears instantly — apply again to reverse.
- Click Copy to copy the result.
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Frequently Asked Questions
FAQs about ROT13 Encoder / Decoder
What is ROT13?
ROT13 is a Caesar cipher with a shift of 13. Each letter is replaced by the letter 13 positions after it in the alphabet (wrapping around). "A" becomes "N", "B" becomes "O", etc.
Why is ROT13 self-inverse?
Because the English alphabet has exactly 26 letters and 13 × 2 = 26, applying ROT13 twice always returns the original text. The same function encodes and decodes.
Does ROT13 encrypt my data securely?
No. ROT13 is a trivial cipher with no cryptographic security. It is used to obscure spoilers or punchlines, not to protect sensitive data.
Are numbers and symbols affected?
No. Only the 26 letters of the Latin alphabet (a–z, A–Z) are rotated. All other characters — numbers, punctuation, spaces — pass through unchanged.
Is my data safe?
Yes. ROT13 is computed entirely in your browser.