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Client-side ProcessingUpdated 2026-02-11Report issue

Runs fully in your browser. Inputs stay on your device. See recent fixes on changelog.

Caesar Cipher Encoder / Decoder

Shift letters by a fixed number to encode or decode text.

FreeRuns in browsercaesar ciphercaesar cipher decoder

Classic substitution cipher — each letter is shifted by a fixed amount.

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Cmd/Ctrl+Enter Primary actionCmd/Ctrl+Shift+L Load sampleCmd/Ctrl+Shift+X Clear/resetCmd/Ctrl+Shift+C Copy result

About Caesar Cipher Encoder / Decoder

Shift letters by a fixed number to encode or decode text. Encode and decode text with the Caesar cipher online for free. Adjustable shift value with brute-force decode option to try all 26 possible rotations. Implements standard encoding and decoding algorithms that produce output compatible with all major programming languages and platforms. Supports both encoding and decoding in a single interface. Everything runs client-side in your browser for maximum speed and privacy — no data is sent to any server, and no signup is required.

Related tools: Vigenere Cipher Encoder / Decoder, Atbash Cipher Encoder / Decoder, Rail Fence Cipher Encoder / Decoder

How to Use Caesar Cipher Encoder / Decoder

  1. Enter text or data in the input field.
  2. Click Encode or Decode depending on your goal.
  3. Copy the output to your clipboard.

Frequently Asked Questions

What is Caesar Cipher Encoder / Decoder?
Encode and decode text with the Caesar cipher online for free. Adjustable shift value with brute-force decode option to try all 26 possible rotations.
What encoding standards are used?
This tool follows the official encoding specifications, including RFC standards where applicable. The implementation matches widely-used libraries so the output is compatible with other systems and programming languages.
Can I encode binary data?
The tool primarily handles text input, but many encoding formats such as Base64 are designed to represent binary data as text. You can paste Base64-encoded binary data for decoding or encode text into a binary-safe format.
Is the encoding reversible?
Yes, all encoding operations provided by this tool are fully reversible. You can encode text and then decode it back to get the exact original content without any data loss.
Is Caesar Cipher Encoder / Decoder free to use?
Yes, encoding and decoding are completely free with no usage limits. The tool runs in your browser and requires no registration.
Is my data safe when using Caesar Cipher Encoder / Decoder?
Yes, all encoding and decoding happens locally in your browser. No data leaves your device, so your input remains completely private.

Related Tools

Vigenere Cipher Encoder / Decoder
Encode and decode text using the Vigenere polyalphabetic cipher.
Atbash Cipher Encoder / Decoder
Reverse the alphabet to encode or decode text with Atbash.
Rail Fence Cipher Encoder / Decoder
Encode and decode text using the rail fence transposition cipher.