ROT

ROT13 & Caesar Cipher

Encode or decode text using ROT13 (shift 13) or any custom Caesar cipher shift from 1–25. Supports encode and decode.

Shift (1–25):

Presets:

Input Text

Encoded (shift 13)

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Cipher Map (A→N):

About Caesar Cipher

The Caesar cipher is one of the oldest encryption techniques, named after Julius Caesar who used it to protect military messages. Each letter is shifted by a fixed number of positions in the alphabet. ROT13 (shift of 13) is a special case where encoding and decoding use the same shift, since the alphabet has 26 letters. It is often used online to hide spoilers. For decoding, apply the same shift — or use 26 minus the original shift.

FAQ

How do I decode ROT13?

Apply ROT13 again — because 13+13=26, encoding and decoding use the same operation.

How do I decode other Caesar ciphers?

To decode a Caesar cipher with shift N, use shift (26-N). E.g. to decode shift-3, use shift-23.

Does it work on numbers and symbols?

Only letters (A-Z, a-z) are shifted. Numbers, spaces, and symbols are passed through unchanged.