Caesar Cipher Encrypt & Decrypt
The classic shift cipher with an adjustable shift amount. This tool does both encrypt and decrypt on one page — just pick a mode, paste your text, and click. Everything runs on your device, nothing is sent to a server.
Everything runs in your browser. Your data is never sent to our servers.
Example
Example Input
Hello (shift 3)
Example Output
Khoor
How to Use
- 1Choose Encrypt or Decrypt mode at the top.
- 2Type or paste your text into the Input field.
- 3If needed, open "More settings" to configure the shift amount.
- 4Click the button (or press Ctrl+Enter) to process. The result appears in the Output field.
- 5Click Copy to copy the result, or "Swap input/output" to quickly reverse the operation.
About Caesar Cipher
The Caesar Cipher shifts each letter by a fixed number of positions in the alphabet — named after Julius Caesar, who reputedly used it for secret messages. ROT13 is a Caesar with a shift of 13.
How it works: choose a shift amount in "More settings"; each letter is shifted by that much (encrypt), and shifted back on decrypt. Digits and symbols are left untouched.
The Caesar Cipher is a classic introduction to cryptography and puzzles. It is trivially breakable (only 25 possibilities), so use it for education or games only, not security.
FAQ
Can this Caesar Cipher tool both encrypt and decrypt?
Yes. This is a single page with a toggle — use Encrypt mode to transform text, and Decrypt mode to reverse it. No need for two separate pages.
Is my data sent to a server?
No. Caesar Cipher is processed entirely in your browser. The text you enter never leaves your device.