Caesar Cipher Decoder and Encoder

Encode or decode text with the classical Caesar cipher (shift 3)

Use this free online Caesar cipher encoder and decoder to quickly shift letters by 3 (the classical Caesar choice). Ideal for puzzles, classroom demos, and quick text transforms — not for protecting sensitive data.

How to use

• Paste your text into the editor.
• Open the Convert menu and choose Encode or Decode (the tool applies a fixed shift of 3).
• Click Convert / Apply to see the result immediately.

What the tool does

• Implements the classical Caesar (shift) cipher with a fixed shift of 3.
• Shifts alphabetic characters forward or backward by 3 positions (A 14 D for encode). Common implementation: letters are shifted; other characters remain unchanged.
• No automatic shift detection, brute-force, or custom-shift option on this page 12 it is a classical Caesar encoder/decoder only.

Common use cases

• Teaching substitution ciphers and basic cryptography.
• Generating simple puzzle clues or treasure-hunt messages.
• Quickly encoding or decoding short messages for games and exercises.

Examples (classical shift = 3)

Plain:  HELLO
Cipher: KHOOR

Plain:  ATTACK AT DAWN
Cipher: DWWDFN DW GDZQ

Plain:  Hello, World!
Cipher: Khoor, Zruog!

Tips & edge cases

• Caesar is trivial to reverse. Use it for learning and fun, not for security.
• If you encounter text with mixed case, most classical implementations preserve case when shifting letters.
• If you don019t know the shift used on an unknown ciphertext, try common shifts manually or use a dedicated solver that tests all 25 shifts.

FAQ

Can the tool try all shifts (brute-force) to find readable output?

No. This page implements the classical Caesar cipher only and uses a fixed shift of 3. It does not perform automatic brute-force or detection.

What shift does the tool use?

The tool always uses shift = 3 (the historical/classical Caesar choice).

Can I change the shift value?

No. This page offers the classical Caesar behavior only. For variable-shift encoding/decoding, look for a general Caesar solver elsewhere.

How do I decode if I don't know the shift?

Manually try common shifts (1025) or use a solver that tests all shifts and highlights readable results. Manual inspection often finds meaningful English quickly.

Is the cipher secure?

No. The Caesar cipher is a simple substitution cipher and can be broken easily. Use modern encryption for any sensitive data.

Related tools

• ROT13 Decoder and Encoder 012 another fixed-shift cipher (shift 13).
• Morse Code Decoder and Encoder 012 translate to/from Morse.
• Base64 Encoder and Decoder 012 convert binary data to text-safe encoding.