Caesar cipher encoder and decoder
Encode or decode ASCII letters with a chosen Caesar shift.
Local processing · Nothing is uploaded · 1 MB input limit
Input & settings
Ready. Enter your input to begin.
How to use this tool
Choose the shift and operation. Uppercase and lowercase are preserved, while other characters remain unchanged.
Limits and behavior
This historical substitution cipher provides no security. Shifts are whole numbers from -1,000 to 1,000 and wrap modulo 26. Input is limited to 1 MB and output to 3 MB. No input content is saved by CraftAI.
Caesar Cipher Encoder & Decoder
Rotate supported Latin letters by a chosen shift for puzzles and demonstrations. Use it for inspecting or preparing your own text, and review the output before replacing the original.
Is Caesar cipher secure encryption?
No. It is easily reversed and unsuitable for protecting secrets.
Related tools: rot13 text encoder · a1z26 cipher