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Home / Validate RFC Format

Validate the Format of an RFC

Check that an RFC (Mexican tax ID) is written correctly: type of person, date, and check digit. Nothing is sent to any server.

No sign-up and nothing uploaded to a server: everything happens in your browser. See for yourself.

How to use: Validate RFC Format

  1. Type the 12- or 13-character RFC.
  2. See whether the format and check digit are correct.
  3. If something fails, check what you typed.

Frequently asked questions

Does it query the SAT?

No. It only validates the RFC structure in your browser.

What are generic RFCs?

XAXX010101000 (general public) and XEXX010101000 (foreigners) are accepted as generic.

Is the RFC sent anywhere?

No, the check happens in your browser.

About this tool

An individual's RFC has 13 characters (4 letters, date of birth YYMMDD, and 3 homoclave characters); a company's has 12 (3 letters, date of incorporation, and homoclave).

The last position is a check digit calculated from the other characters, which helps detect typing errors.

This tool only checks the structure. It doesn't confirm that the RFC is registered or who it belongs to: for that, there's the SAT's official lookup.

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