Caesar Cipher
Encrypt and decrypt Caesar cipher text with a custom shift. Free tool for puzzles and history lessons—copy paste, adjustable key.
About Caesar Cipher Tool
The Caesar cipher shifts each letter by a fixed number (the key). Julius Caesar reportedly used shift 3; you can choose any offset for encoding and decoding.
How to Use Caesar Cipher Tool
Enter text and pick a shift value (e.g. 3). Encode for puzzles or decode a clue you received. Share the shift separately so solvers can decrypt.
When to Use Caesar Cipher Tool
Education: Demonstrate frequency analysis on simple ciphers. Games: Layer Caesar under other puzzle steps. History: Connect students to classical cryptography.
Why Use This Caesar Cipher Tool?
Interactive shifts beat paper wheels when testing multiple keys quickly.
Unicode vs HTML formatting
ROT13 is Caesar with shift 13. Vigenère adds multiple keys—Caesar is the simplest alphabet rotation.
Platform compatibility
Classroom history lessons, escape rooms, and beginner cryptography modules. Not for real secrets.
Examples
- HELLO shift 3 → KHOOR
- KHOOR shift -3 → HELLO
- Shift 13 matches ROT13
Frequently asked questions
How do I break a Caesar cipher?
Try all 25 shifts or use frequency analysis—only 26 possibilities for English.
Caesar vs substitution cipher?
Caesar shifts the alphabet uniformly. General substitution maps letters arbitrarily.