Caesar Cipher Encoder and Decoder
The Caesar cipher is one of the oldest known encryption methods, named after Julius Caesar, who used it to protect military messages. It works by shifting every letter a fixed number of places down the alphabet, so with a shift of three, A becomes D and Z wraps around to C. This tool lets you pick any shift from one to twenty five, encrypt your text, and decrypt it by applying the opposite shift. It is a classic teaching example of how substitution ciphers work and a fun way to pass simple coded notes, though it offers no real security by modern standards. Letter case is kept and non letters are untouched. Everything happens locally in your browser, so your messages stay private.
How to use Caesar Cipher
- Enter your text.
- Choose a shift from 1 to 25.
- Select encrypt or decrypt.
- Copy the transformed text.
Frequently asked questions
What shift values can I use?
You can set any shift from 1 to 25, and each letter moves that many places along the alphabet.
How do I decrypt a Caesar cipher?
Decrypting uses the opposite shift, so if it was encrypted with a shift of 3, decrypt with a shift of 3 in the decode direction.
How is Caesar cipher different from ROT13?
ROT13 is a fixed Caesar cipher with a shift of 13, while this tool lets you pick any shift value from 1 to 25.
What is Caesar Cipher?
The Caesar cipher is one of the oldest known encryption methods, named after Julius Caesar, who used it to protect military messages. It works by shifting every letter a fixed number of places down the alphabet, so with a shift of three, A becomes D and Z wraps around to C.
Is Caesar Cipher free to use?
Yes. Caesar Cipher is completely free, with no sign-up and no usage limits.
Does Caesar Cipher work in a web browser?
Yes. Caesar Cipher runs in any modern web browser. There is nothing to download or install.
Is my data private with Caesar Cipher?
Yes. Caesar Cipher runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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