Caesar Cipher Encoder & Decoder
Encode and decode text with a Caesar cipher, or brute-force all 26 shifts. Free online cipher tool for learning classic encryption.
Frequently asked questions
- What is a Caesar cipher?
- One of the oldest ciphers: every letter is shifted a fixed number of places in the alphabet, so A becomes D with a shift of 3.
- How do I decrypt a message?
- Set the same shift and choose Decrypt, or simply use a shift of 26 minus the original.
- Is it secure?
- No. With only 25 possible shifts it is broken instantly by brute force. Use it for puzzles and learning, never for real secrets.
- Are numbers and punctuation kept?
- Yes, only letters are shifted. Capitalization, spaces and punctuation stay exactly where they were.
This tool runs entirely in your browser. No data is uploaded anywhere.