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ROT13 Encoder / Decoder
Encode or decode text with the ROT13 substitution cipher. Apply it twice to get the original text back.
✓ Free
✓ Instant
✓ No Signup
Result
Result will appear here...
What is ROT13?
ROT13 replaces each letter with the letter 13 places after it in the alphabet. Because the alphabet has 26 letters, applying ROT13 twice returns the original text, so the same operation encodes and decodes.
It is commonly used in forums to hide spoilers and puzzle answers so readers have to choose to reveal them.
Key facts
- Only letters change; numbers and punctuation stay the same
- A becomes N, B becomes O, and so on
- It is obfuscation, not encryption
- Running it twice restores the original
💡 Tip: Never use ROT13 to protect sensitive information. It is trivially easy to reverse.
Frequently Asked Questions
Is ROT13 secure?
No. It provides no real security and is only used to hide spoilers or lightly obscure text.
How do I decode ROT13?
Paste the encoded text and click the button again. The same operation reverses itself.
Is my text saved or sent to a server?
No. Everything runs locally in your browser with JavaScript. Your text never leaves your device and we never see it.