Caesar Cipher
Encode and decode text with a Caesar shift cipher. Choose any shift from 1 to 25.
The Caesar cipher shifts each letter by a fixed number of places — the classic cipher said to be used by Julius Caesar. Caesar Cipher lets you encode and decode text with any shift from 1 to 25, for puzzles, teaching and lightweight obscuring.
How to use caesar cipher
- 1. Paste your text.
- 2. Choose a shift amount (1–25) and encode or decode.
- 3. Copy the result.
When to use Caesar Cipher
Puzzles and games
Create or crack a shifted-cipher message.
Teach cryptography basics
Demonstrate how a substitution cipher works with an adjustable shift.
Casual obscuring
Scramble text so it isn't readable without knowing the shift.
Frequently asked questions
How do I decode a Caesar message?
Apply the opposite shift, or decode with the same shift used to encode. ROT13 is just a Caesar cipher with a shift of 13.
Is it secure?
No — with only 25 possible shifts it's trivial to break. Use it for fun and learning, not protection.
Is my text private?
Yes — it's processed in your browser.