Caesar Cipher / ROT13
Classic shift cipher. Default shift 13 = ROT13. Encode and decode in one tool.
11325
Effective shift: 13
About Caesar Cipher / ROT13
Type or paste text, pick a shift amount, and the tool moves each letter that many positions through the alphabet. With the default shift of 13 it acts as ROT13, where running the same operation twice returns the original text. Numbers, spaces, and punctuation pass through unchanged.
The conversion happens entirely in your browser, so nothing you enter is sent anywhere. The Caesar cipher is a teaching example and a way to lightly obscure spoilers or puzzle answers, not real encryption; do not use it to protect sensitive information.
Frequently asked questions
- What is the difference between Caesar cipher and ROT13?
- ROT13 is simply a Caesar cipher with a fixed shift of 13, which makes encoding and decoding the same operation.
- Does it shift numbers and symbols?
- No. Only alphabet letters are shifted; digits, spaces, and punctuation stay exactly as you entered them.
- Is a Caesar cipher secure?
- No. With only 25 possible shifts it can be broken in seconds, so treat it as a puzzle tool rather than encryption.