RFC Validator and Generator

Validate a Mexican RFC (individuals and companies) with its homoclave and check digit, and generate test RFCs. Free, in your browser, nothing is sent.

Generate test numbers
Generated numbers are fictitious and only for testing software and forms. Using them to pass yourself off as someone, open accounts or register anything is illegal.
What it does
The RFC (Registro Federal de Contribuyentes) is the Mexican tax ID issued by the SAT. Individuals have 13 characters (four letters from the name, the date of birth YYMMDD and a three-character homoclave); companies have 12 (three letters from the name and the date of incorporation). The last character of the homoclave is a check digit calculated with modulo 11, and the SAT never issues initials that form offensive words.
Everything happens in your browser: the numbers you type are not sent or stored.
Frequently asked questions
Does a valid number mean that the person or company exists?
No. It only means the check digits are correct, which catches typing mistakes. Whether the number was actually issued, and to whom, can only be checked with the authority that issues it.
What are the generated numbers for?
For testing: filling in forms in development, testing databases and validation code. They are made at random with correct check digits, so by chance one may coincide with a real number. Never use them to identify yourself, sign up for anything or deceive anyone.
How does a check digit work?
It is calculated from the other digits with a fixed formula, usually multiplying each digit by a weight and taking the remainder of a division (modulo 11, or modulo 23 for the Spanish DNI letter). If one digit is typed wrong or two are swapped, the check digit no longer matches.
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