Encode and decode text with a Caesar cipher — each letter shifts a fixed number of places through the alphabet. A Caesar cipher is simple letter substitution for puzzles and fun, not secure encryption.
Please note: a Caesar cipher is simple letter substitution — fun for puzzles, but not secure encryption. Never use it to protect real secrets.
Mode
How to Use
- Type or paste your text into the input box.
- Drag the shift slider to choose how many places each letter moves (1–25).
- Pick Encode to scramble text or Decode to unscramble it.
- Copy the result with one click, or clear to start again.
Key Features
- Live encoding — the result updates as you type.
- Any shift 1–25 — not just the classic shift of 3.
- Encode and decode — reverse any Caesar cipher instantly.
- Keeps letter case — capitals stay capital, punctuation untouched.
- 100% private — runs entirely in your browser; nothing is sent or stored.
FAQs
Is a Caesar cipher secure?
No. It is simple letter substitution with only 25 possible shifts, so anyone can crack it in seconds. Use it for puzzles and fun, never for real secrets.
How do I decode a message?
Paste the coded text, switch the mode to Decode and set the same shift that was used to encode it.
What happens to numbers and punctuation?
They pass through unchanged — only the letters A to Z (upper and lower case) are shifted.
Is my text sent anywhere?
No. The cipher runs entirely in your browser and never transmits or saves your text.
Related Tools
Try these related tools: ROT13 Encoder, Base64 Encoder and Morse Code Translator.