HELLO, shift 3 encode
Before
HELLO
After
KHOOR
Caesar Cipher Converter
Encrypt or decrypt with a classic Caesar shift from 1 to 25—set the key, pick encode or decode, and read results live.
Caesar Cipher Converter
Adjust shift and mode — output updates live.
Quick shift
Text to shift forward or backward
Shifted result
Input: 0 chars
Output: 0 chars
Letters shifted: 0
Digits unchanged: 0
Symbols unchanged: 0
Current shift: 3 (encode)
Your text stays in your browser — nothing is uploaded.
How to Use
- Set the shift amount from 1 to 25 (default 3 — the classic Caesar shift).
- Choose Encode to encrypt or Decode to decrypt with the same shift value.
- Use quick presets for ROT13, Shift +1, Shift +3, or enable Show all shifts to preview every decode attempt.
- Copy, download, or toggle highlight to see which letters were shifted.
Example
Plaintext (shift 3, encode)
HELLO
Ciphertext
KHOOR
Before and After Examples
KHOOR, shift 3 decode
Before
KHOOR
After
HELLO
ABC XYZ, shift 3
Before
ABC XYZ
After
DEF ABC
Room 101, shift 13
Before
Room 101
After
Ebbz 101
Caesar Cipher, shift 5
Before
Caesar Cipher
After
Hfjxfw Hnumjw
What This Tool Does
Caesar Cipher Converter shifts each Latin letter forward or backward in the alphabet by your chosen amount from 1 to 25. Encode rotates letters forward; decode applies the inverse shift. Numbers, punctuation, and spaces pass through unchanged. Enable brute force preview to try all 25 decode shifts at once.
How Caesar Cipher Works
Shift letters
A shift of 3 turns A into D, B into E, and C into F.
Wrap alphabet
Letters near the end wrap around — X with shift 3 becomes A.
Preserve case
HELLO and hello keep their letter case in the output.
Non-letters stay unchanged
Numbers, spaces, and punctuation are not shifted.
Decode reverses the shift
Shift 3 encode is decoded by shifting back 3 positions in the alphabet.
Caesar Alphabet Reference
Each shift maps every letter to a new position. ROT13 is Caesar cipher with shift 13 — the same operation encodes and decodes.
Shift 3
A → D
B → E
C → F
X → A
Y → B
Z → C
Shift 13 (ROT13)
A → N
B → O
M → Z
N → A
ROT13 is Caesar cipher with shift 13. Use the ROT13 Converter for the dedicated symmetric tool.
Caesar Cipher vs ROT13
Choose the Caesar Cipher Converter for custom shifts and brute force decoding. Use ROT13 when you know the shift is exactly 13.
| Task | Best tool |
|---|---|
| Custom shift amount | Caesar Cipher Converter |
| Fixed shift 13 | ROT13 Converter |
| Decode unknown shift | Caesar brute force view |
| Puzzle hints | ROT13 Converter |
| Learning classical ciphers | Caesar Cipher Converter |
Common Uses
Classroom cryptography
Puzzle hunts
Escape room clues
CTF warmups
Caesar cipher homework
Historical cipher demos
Word games
Secret message practice
Security Note
Caesar cipher is not secure encryption. It is a simple substitution cipher and should not be used for passwords, tokens, private data, or sensitive messages.
Popular Workflows
Notes & Limitations
All conversion runs locally in your browser. Only basic Latin A–Z and a–z letters shift; accented characters, Cyrillic, CJK, and emoji pass through unchanged.
Frequently Asked Questions
What shift did Caesar historically use?
Classical accounts describe Julius Caesar using a shift of 3. That is why shift 3 is the default in this converter and is often called the classic Caesar cipher.
What does shift 3 mean?
Each letter moves three positions forward in the alphabet during encode. A becomes D, B becomes E, and letters near Z wrap around to the start.
How do I decrypt a Caesar cipher?
Select Decode, enter the same shift value used during encryption, and paste the ciphertext. The original plaintext appears in the output panel.
What is brute force decoding?
Brute force tries every possible shift from 1 to 25. Enable Show all shifts to preview all decode attempts and spot readable plaintext when the shift is unknown.
Is shift 13 the same as ROT13?
Yes. A Caesar cipher with shift 13 on Latin letters behaves exactly like ROT13 — encoding and decoding use the same operation.
Are numbers and punctuation changed?
No. Digits, spaces, and punctuation are copied exactly as typed. Only A–Z and a–z letters are shifted.
Are accented letters shifted?
No. Only basic Latin A–Z and a–z rotate. Accented letters, Cyrillic, Greek, and other Unicode letters pass through unchanged.
Is Caesar cipher secure?
No. With only 25 possible shifts, Caesar cipher is trivial to break. Use it for learning, puzzles, and demos — never for real secrets.
Can I decode without knowing the shift?
Yes. Enable Show all shifts or click Brute force all shifts to preview decode results for shifts 1 through 25 and find readable plaintext.
Is my text uploaded?
No. All Caesar cipher conversion runs entirely in your browser — nothing is sent to a server.
Can I download the result?
Yes. Click Download .txt to save the output as a plain-text file on your device.