ROT13 Encoder and Decoder

Encode and decode Latin letters with ROT13 or a custom rotation. The conversion runs live and directly in your browser.

Use 0 to show every rotation from 1 to 25.

With a rotation of 13, encoding and decoding produce the same result.

Latin letters are shifted by the selected rotation. All other characters remain unchanged.

What this tool does

ROT13 replaces every ASCII letter with the letter that is 13 positions away in the alphabet.

The optional rotation lets the same interface handle other Caesar shifts as well.

How to use the tool

  1. Type or paste text into the field on the left.
  2. Choose Encode or Decode and select a rotation from 1 to 25 when needed.
  3. Set the rotation to 0 when you want to compare every possible letter rotation.

Useful applications

  • Read spoiler notices or hints that use ROT13.
  • Work through a known Caesar shift for a learning exercise.
  • Inspect every possible rotation when the original shift is unknown.

Notes and limitations

  • ROT13 and other Caesar shifts do not protect confidential data.
  • Only the characters A to Z and a to z are rotated.
  • The conversion runs in the browser, so text is not sent to petuja.tools for this feature.

Frequently asked questions

Why are encoding and decoding the same for ROT13?

A 13-position rotation reverses itself when it is applied a second time.

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