Free ROT13 Cipher Tool
Quick Tips
- • This tool runs entirely in your browser - your data stays private.
- • Press Ctrl+V (Cmd+V on Mac) to quickly paste text.
- • Use the Copy button to save your result to clipboard.
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Encode and decode text using ROT13 letter substitution cipher.
Your Recent Tools
Examples
Hello World
Uryyb Jbeyq
Uryyb Jbeyq
Hello World
The secret answer is: 42
Gur frperg nafjre vf: 42
ROT13
EBG13
Why Use This Tool?
What problems does this solve?
You need to hide text content from casual reading without needing keys or passwords. ROT13 obscures text enough that readers must actively choose to decode it, perfect for spoilers and puzzle answers.
Common use cases:
- Hiding movie/book/game spoilers in discussions
- Obscuring puzzle and quiz answers
- Internet culture and nostalgia references
- Basic email address obfuscation
- Learning about substitution ciphers
Who benefits from this tool?
Forum and community moderators hiding spoilers. Puzzle creators obscuring answers. Students learning basic cryptography. Internet culture enthusiasts.
Privacy first: All encoding happens locally in your browser. Your text never leaves your device.
Frequently Asked Questions
No, ROT13 provides no security whatsoever. It is trivial to decode. Use it only for hiding spoilers or mild obfuscation, never for protecting sensitive information.
The English alphabet has 26 letters, and 13 is exactly half. This makes ROT13 self-inverse - the same operation encodes and decodes. Other rotation values would require different operations to reverse.
ROT13 only affects letters A-Z and a-z. Numbers, punctuation, spaces, and other characters remain unchanged. This preserves text structure and readability cues.
Encryption uses secret keys and complex mathematics to protect data. ROT13 is a simple, keyless letter substitution that anyone can reverse instantly. It is obfuscation, not protection.
Usenet and forums for spoilers, puzzle and quiz answer hiding, very basic email address obfuscation (ineffective against modern harvesters), and as a cultural reference in tech communities.
Yes, that would be a general Caesar cipher. ROT13 is just Caesar cipher with shift=13. See our Caesar Cipher tool for customizable rotation values.
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