ROT13 / Caesar Cipher
Apply a Caesar cipher with a configurable shift amount. ROT13 uses shift 13.
Apply ROT13 or any Caesar cipher shift to encode and decode text. Simple letter-substitution encryption.
How to Use
- 1 Paste your input text
- 2 Choose encode or decode
- 3 Copy the result instantly
Why Use This Tool
Private & Secure
Your data never leaves your device. Everything is processed right in your browser — nothing is uploaded or stored on any server.
Lightning Fast
No waiting for uploads or server processing. Results appear instantly because all the work happens on your machine.
Free, No Sign-Up
Use this tool as many times as you want. No account required, no email, no limits — just open and go.
Frequently Asked Questions
Is ROT13 Cipher free to use?
Yes, ROT13 Cipher is completely free with no usage limits, no account required, and no ads. You can use it as many times as you need.
Is my data safe when using ROT13 Cipher?
Absolutely. ROT13 Cipher runs entirely in your browser. Your files and data are never uploaded to any server — everything is processed locally on your device.
Is there a character or text length limit for ROT13 Cipher?
There is no hard limit. ROT13 Cipher can handle very long texts, though extremely large inputs (millions of characters) may slow down depending on your device.
Can I use ROT13 Cipher on my phone?
Yes, ROT13 Cipher works on any device with a modern browser — including phones and tablets. The interface adapts to your screen size automatically.