Caesar Cipher
Encode or decode text using the classic Caesar cipher. Choose any shift value from 1 to 25 to encrypt or decrypt your message.
About This Free Online Caesar Cipher
Our free online Caesar cipher tool lets you encrypt and decrypt text using the classic Roman cipher named after Julius Caesar. Choose any shift value from 1 to 25 to rotate letters in the alphabet. Shift by 3 for the traditional Caesar cipher, or use any other value for your own variation. The tool handles both uppercase and lowercase letters while preserving spaces, numbers, and punctuation.
Features of Our Caesar Cipher
- Adjustable shift value from 1 to 25
- Encrypt and decrypt with the same tool
- Type text to encrypt, paste ciphertext to decrypt
- Preserves case, spaces, numbers, and punctuation
- Copy encrypted/decrypted text to clipboard
- 100% private — browser-only processing
How to Use the Caesar Cipher
Using this tool is simple and requires no signup or registration. Follow these steps:
- Type or paste your message into the input area.
- Set the shift value (1-25). Shift by 3 for the classic Caesar cipher.
- The result appears instantly below.
- To decrypt, paste the ciphertext and set the same shift value.
Frequently Asked Questions About Caesar Cipher
What is the Caesar cipher?
The Caesar cipher is one of the oldest known encryption techniques, used by Julius Caesar to communicate with his generals. Each letter in the plaintext is shifted a fixed number of positions down the alphabet. For example, with a shift of 3, A becomes D, B becomes E, and so on.
How do I decrypt a message?
Decryption is the same as encryption but in reverse. Paste the ciphertext and set the same shift value used for encryption. The tool will shift letters back to their original positions.
Is the Caesar cipher secure?
No. The Caesar cipher is extremely easy to break with only 25 possible keys (shifts). It is used for educational purposes, puzzles, and basic obfuscation but should never be used for real security.
Why Choose Text Toolbox?
Text Toolbox provides free, private, and instant online text tools. Unlike other text utility websites that require signup accounts or send your data to servers, all our tools process your text entirely in your browser. This means your content never leaves your device — we cannot see it, store it, or share it. Our tools are fast, lightweight, and work on any device with a modern web browser.