Caesar Cipher
Encode or decode text with a custom letter shift to explore classical substitution ciphers.
FreeBrowserAbout Caesar Cipher
Shift Latin letters through the alphabet to encode or decode a Caesar cipher. Compare the result as you change the shift while keeping punctuation, numbers and spaces intact.
When to use this tool
- Explore a classical cipher in a lesson.
- Solve a simple alphabet-shift puzzle.
Limits to know before using it
Caesar ciphers provide no meaningful modern secrecy. Only A–Z letters rotate; other characters remain unchanged.
Data handling and cost
The main operation runs in your browser; tool input is not uploaded for processing. The site can still use session cookies and collect operational or usage data as described in the privacy policy.
Free to use in your browser, with no sign-in needed.
Frequently Asked Questions
No. Caesar cipher is a historical learning and puzzle cipher. Use Symmetric Encryption for real confidential text.
Only English A-Z and a-z letters are shifted. Case is preserved, while numbers, punctuation, whitespace, and accented characters are left unchanged.
Switch to Decode and use the same shift value that was used to encode the original message.