Caesar Cipher
Encode and decode Caesar-shifted text with an adjustable key.
Ciphertext
How the Caesar cipher works
Example
Attack at dawn! Converted instantly in your browser - A Caesar cipher shifts each letter by a fixed number of positions in the alphabet.
- With a shift of 3, A becomes D, B becomes E, and Z wraps around to C.
- The same shift in reverse decodes the message. Punctuation and spacing remain unchanged.
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Frequently asked questions
Is the Caesar cipher secure?
No. It is a historical substitution cipher that is useful for learning and puzzles, not modern security.
Is my input uploaded?
No. EncodeLab performs this conversion locally in your browser. Your input is not sent to an EncodeLab server or stored by us.
What shift did Julius Caesar use?
The cipher is traditionally associated with a shift of 3.
Are numbers and punctuation shifted?
No. This tool shifts Latin letters only.