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Caesar Cipher Encoder / Decoder

Encode or decode text with the Caesar shift cipher and try all 25 shifts at once.

Runs in your browser Free
Processed locally in your browser.
Try all 25 shifts (brute force)

Only the Latin letters A–Z are shifted; other characters stay unchanged. This is a classic puzzle cipher, not encryption.

What is the Caesar cipher?

The Caesar cipher is one of history's best-known encryption methods: every letter is shifted a fixed number of places in the alphabet. It's named after Julius Caesar, said to have shifted his military messages by 3. With a shift of 3, 'HELLO' becomes 'KHOOR'.

Encryption and brute force

  • Choose a shift to encrypt or decrypt text
  • Don't know the key? The brute-force table shows all 25 possible decryptions at once so you can spot the meaningful one

Where it's used

A fun, educational tool for escape room puzzles, treasure hunts, classroom activities and introductions to cryptography. Everything happens in your browser.

How to use Caesar Cipher Encoder / Decoder

  1. Type the text to encrypt or decrypt.
  2. Choose the shift amount.
  3. Select encode or decode.
  4. If the key is unknown, find the answer in the brute-force table.

Why use this tool?

Offers both encryption and a table of every possibility, ideal for puzzle makers and solvers.

FAQ

Is the Caesar cipher secure?

No. With only 25 possible keys it can be broken instantly; use it for fun, never for real secrets.

Are accented letters supported?

The cipher works on the 26 Latin letters; other letters and digits are left unchanged.

How is it different from ROT13?

ROT13 is a Caesar cipher with a shift of 13. Apply it in one click with the ROT13 tool.

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