ROT18 Encoder and Decoder

Transform letters with ROT13 and digits with ROT5. The combined ROT18 conversion runs directly in the browser.

Letters receive ROT13 and digits receive ROT5. Punctuation and other characters stay unchanged.

What this tool does

ROT18 combines ROT13 for Latin letters with ROT5 for decimal digits.

This keeps a mixed string of text and numbers consistently transformed in one step.

How to use the tool

  1. Enter the text that contains letters or digits into the input field.
  2. Choose Encode or Decode to get the transformed string immediately.
  3. Use Copy to take the result without selecting it manually.

Useful applications

  • Read a ROT18 string from an old forum or technical note.
  • Demonstrate the combination of ROT13 and ROT5 in a lesson.
  • Compare mixed sample values of letters and numbers with a fixed rotation.

Notes and limitations

  • ROT18 is not a method for protecting secrets or credentials.
  • The letter rotation and digit rotation are both self-inverse.
  • Text remains on your device for this browser-based feature.

Frequently asked questions

How does ROT18 differ from ROT13?

ROT18 rotates digits 0 to 9 with ROT5 in addition to rotating letters.

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