ROT13 Cipher
Encode text with ROT13, ROT5, ROT18, or ROT47
About
Apply the ROT13 cipher (or any Caesar shift from 1 to 25) to text. ROT13 is its own inverse, so the same operation encodes and decodes. Letter case is preserved and non-letters are left untouched. Everything runs in your browser; nothing is uploaded.
About this tool
Encode and decode text with ROT13 or a configurable Caesar shift (1–25). Case-preserving, instant. Free, client-side, no signup. ROT13 Cipher runs in the browser on DevTools. There is no signup, and your input stays on this device unless the tool explicitly performs a live network lookup.
What this tool does not do
- ROT13 Cipher is a free in-browser utility, not a hosted API. It does not keep server-side history and is not a substitute for production verification in your own stack.
How do I use this tool?
How do I use ROT13 Cipher?
Open ROT13 Cipher, enter or paste your input, and copy the result. The page works without an account.
Related guides
Caesar Ciphers, ROT13, and Why Neither Is Encryption
What a shift cipher is, why ROT13 is self-inverse and useful for light obfuscation, and how frequency analysis breaks even large keys efficiently.
Letter Frequency Analysis: How Frequency Stats Crack Substitution Ciphers
What the letter distribution in English looks like, how to use it to break a Caesar cipher, and what word and line stats reveal that individual letters miss.
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