Caesar Cipher & ROT13 Encoder

Encode and decode text using the Caesar cipher - shift letters by any amount from 1 to 25. ROT13 shifts by 13 and is self-reversing.

Cipher Settings

Quick Presets

0 25

ROT47 mode active - shifts all printable ASCII characters (33-126) by 47 positions. The shift slider does not apply.

Direction

characters · words

ROT47 Output

Output will appear here…

Try These Examples

️ About the Caesar Cipher

Julius Caesar reportedly used a shift of 3 to protect military messages. Each letter in the plaintext is replaced by the letter 3 positions later in the alphabet.

ROT13 (shift 13) is self-reversing - encoding and decoding are the same operation, because 13 + 13 = 26 (a full alphabet cycle).

ROT47 extends the idea to all printable ASCII characters (codes 33-126), shifting each by 47 positions within that range.

ROT13 Cipher Wheel

Each letter maps to the letter 13 positions away. Encode and decode are identical operations.

In AB CD EF GH IJ KL M
Out NO PQ RS TU VW XY Z
In NO PQ RS TU VW XY Z
Out AB CD EF GH IJ KL M

Use Cases

  • • Encode spoilers in online forums
  • • Create simple puzzle messages
  • • Learn the basics of classical cryptography
  • • ROT13 is used in Usenet newsgroups to hide content
  • • Practice shift cipher decoding by hand

Related Tools

→ Morse Code Translator → Binary Translator → Leet Speak Translator