Caesar Cipher Decoder
Encode and decode Caesar ciphers instantly. Set a shift and watch plaintext ↔ ciphertext update live.
Plaintext
This page is dedicated to Caesar Cipher Decoder.
Letters only.
Offset shifts the starting zig-zag position before placing the first character.
Ciphertext
Caesar Cipher Decoder — explanation, history & tips
Family: Substitution
Era: Ancient Rome
Strength: Very weak
The Caesar cipher shifts each letter by a fixed number of positions in the alphabet. Choose a shift (for example 3), and this tool will encode plaintext into ciphertext or decode ciphertext back to readable text in real time.
- Pick Encode or Decode.
- Enter your text on the left (encode) or right (decode).
- Set the shift value (0–25).
- Copy the result instantly—no submit button.
History (quick)
Traditionally attributed to Julius Caesar for military messages. It’s the classic “shift” cipher and a common first example in cryptography and puzzle hunts—easy to break today with frequency analysis or brute force.
Quick FAQs
What shift did Caesar actually use?
The famous historical association is a shift of 3, but in puzzles you’ll see any shift from 0–25.
How do you break a Caesar cipher?
Try all 26 shifts (brute force) or use letter frequency—common in English is E, T, A, O.
Does it keep punctuation and spaces?
Typically yes—only letters are shifted; other characters are left unchanged.
Want to decode with no key? Try our Cipher Breaker →