ROT13 Cipher Tool

Paste text to ROT13-encode it; paste ROT13 text to decode it - the operation is identical both ways.

Encode Decode

Enter text on the left and click Apply ROT13 to begin.

How to use

Why is ROT13 its own inverse?

Because the alphabet has 26 letters, shifting 13 twice brings you back to the start, making encoding and decoding identical.

Is ROT13 secure for protecting data?

No. ROT13 offers no real security. It is trivially reversible and should only be used for casual text hiding.

Does ROT13 affect numbers and punctuation?

No. Only letters A-Z and a-z are shifted. Numbers, spaces, and punctuation pass through unchanged.

What is the difference between ROT13 and Caesar cipher?

ROT13 is a Caesar cipher with a fixed shift of 13. A general Caesar cipher lets you choose any shift value.