Shift every letter of your text by a fixed amount with the cipher Julius Caesar himself used. Encode, decode, or rotate with ROT presets β all in your browser.
The Caesar cipher replaces each letter with the letter a fixed number of positions further along the alphabet. With shift 3, the alphabet becomes DEFGHIJKLMNOPQRSTUVWXYZABC, so HELLO becomes KHOOR. To decode, simply apply the opposite shift β the same tool with the same shift works in reverse. While fun and famous, the Caesar cipher has only 25 possible keys, so modern decryption tools can break it instantly. It remains perfect for puzzles, learning cryptography, and casual message hiding.