ROT13 Cipher
Apply the ROT13 substitution cipher — each letter replaced by the one 13 positions later in the alphabet. ROT13 is self-inverse: apply twice to get the original.
Output will appear here.What powers the ROT13 Cipher
Live encoding as you type
Self-inverse (apply twice = original)
Preserves non-letter characters
Case-preserving (A→N, a→n)
One-click copy
Why the ROT13 Cipher is different
Browser-native
The ROT13 Cipher runs entirely in your browser. Input is processed locally — never uploaded, never logged, never cached anywhere outside your device.
No artificial limits
No daily quotas, no character ceilings, no "upgrade for more" walls. Every feature is the complete feature — the same on the first use as the thousandth.
Production-grade quality
Built to the same engineering bar as paid SaaS tools — accurate algorithms, audited logic, responsive design and accessibility-tested interactions.
Common use contexts
- Hiding spoilers in forum posts
- Light text obfuscation
- Cryptography teaching example
- Puzzle creation
Private and secure
Zero upload
All processing happens in your browser. Input is never transmitted, logged or cached.
Works offline
Once the page loads, the tool runs without an internet connection. No network calls happen during use.
No tracking
No accounts, no cookies for tool state. Only aggregate analytics count visits at the page level.