Caesar Cipher
Shift every letter by a fixed amount — a classic, simple cipher for puzzles and learning, not for securing anything sensitive.
About this tool
A negative shift decodes what a positive shift encoded, and vice versa; non-letter characters are left untouched, and capital letters stay capital. Shift 13 is the same as ROT13, which undoes itself.
If you've been given a Caesar-encoded message without the shift, open Try all 25 to decode: it decodes your text with every possible shift and marks the one that looks most like English. That's exactly why this cipher is trivially breakable, so it's for learning, puzzles and light fun, not for protecting anything.