Caesar Cipher Encoder

Encode or decode text with the ancient Caesar cipher using any letter shift from 1 to 25. A great tool for puzzle solving, CTF challenges and learning classic cryptography.

100% free No uploads Runs in your browser No signup

Caesar cipher

Shift amount: 3

Input text

Encoded (shift +3) — decode with shift 23

—

Julius Caesar's original cipher shifted letters by 3. To decode a message, shift by 26 minus the encoding shift — or just try each shift until the text becomes readable.

How to use the Caesar Cipher Encoder

1
Open the tool above — it is already running, no install or account needed.
2
Enter your input and adjust the options to match what you need.
3
Copy or download the result — everything was processed locally in your browser.

Private by design

This tool runs 100% inside your own browser using local JavaScript — your input never touches a server. That makes it instant, offline-capable in many cases, and private even for sensitive data.

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