Caesar Cipher — Free Online Tool
The Caesar cipher shifts each letter by a fixed number of positions in the alphabet. Shift 3 turns 'A' into 'D'. To decode, shift by the same amount in reverse. ROT13 (shift 13) is its own inverse — apply twice to recover original text.
100% client-side. No uploads. Your data never leaves your browser.
How to use Caesar Cipher
- Enter your text.
- Set the shift value (0-25).
- Choose Encode or Decode.
- Click Apply Cipher.
Frequently Asked Questions
What shift is ROT13?
ROT13 is the Caesar cipher with shift 13. Because 13+13=26, it is its own inverse — applying ROT13 twice gives the original text.
Is Caesar cipher secure?
No. There are only 25 meaningful shifts, and all can be brute-forced in seconds. Use it for fun and puzzles only.
Related tools
Related reading
Browse all free tools · theproductguy.in