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Caesar Cipher Encoder & Decoder

Translators

Encode and decode the Caesar cipher with any shift, including ROT13.

100% private. Processing happens entirely in your browser.
Plain text

The Caesar cipher shifts each letter by a fixed amount (Julius Caesar reportedly used 3). ROT13 (shift 13) is its own inverse — encoding twice returns the original. A historical cipher for fun and learning, not security.

Caesar Cipher Encoder & Decoder lets you encode and decode the Caesar cipher with any shift, including ROT13. Everything runs entirely in your browser, so your text never leaves your device. It’s free, needs no sign-up, and works on any device.

How to use the Caesar Cipher Encoder & Decoder

  1. 1Enter your text. Type or paste your text into the “Plain or cipher text” box.
  2. 2Pick a direction. Use the Swap button to choose which way to translate.
  3. 3Get your result. Read the result instantly. Your shifted text appears in the output box.
  4. 4Copy it. Tap “Copy” to copy the result to your clipboard.

Frequently asked questions

Is the Caesar Cipher Encoder & Decoder free?

Yes. Caesar Cipher Encoder & Decoder is completely free to use, with no sign-up, account, or limits.

Does the Caesar Cipher Encoder & Decoder store or upload my text?

No. This tool processes everything locally in your browser. Your text is never uploaded, stored, or logged.

Can I use the Caesar Cipher Encoder & Decoder on my phone?

Yes. The tool is mobile-friendly with large tap targets and works in any modern browser on phones, tablets, and desktops.

Can it translate both ways?

Yes. Use the Swap button to translate in either direction between plain or cipher text and the result.

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