The RFC Generator creates Mexican Registro Federal de Contribuyentes (RFC) numbers for individuals, following the official algorithm used by SAT: the first four letters come from the surnames and first name, six digits mark the birth date, two characters form the homoclave, and the last one is a check digit computed with a modulo-11 formula over a table of values specific to SAT.
What it is
The RFC identifies every taxpayer in Mexico, similar to Brazil's CPF. A valid RFC isn't just any sequence of letters and digits: the last character is always derived from the 12 before it, and the homoclave (positions 11-12) comes from an algorithm that processes the full name letter by letter. This tool generates RFCs that pass both of those checks, but don't belong to any real person — they exist only to test forms, databases, and integrations that expect the Mexican format.
With it you can:
- Generate one RFC or many at once (in bulk), to fill test spreadsheets and databases.
- Download the list as .txt when generating in bulk.
- Validate an existing RFC on the same page: switch to the Validator tab to check whether a number has the correct check digit.
Important: these numbers are fictitious. Using a fake RFC to impersonate someone or defraud a registry is a crime in Mexico. Use this only for software testing.
How to use it
- Set how many RFCs you need (up to 50 at once).
- Click Generate RFC.
- Copy one result or all of them, or download the list as .txt.
- To check an RFC you already have, use the RFC Validator tab.
How the check digit is calculated
SAT uses two different tables: one for the homoclave (which sums products of digit pairs converted letter by letter) and a separate one for the final check digit — which multiplies each of the first 12 characters by a descending weight from 13 to 2, sums everything, and takes the remainder of dividing by 11. A remainder of 0 gives digit 0; a remainder of 1 gives the letter A; any other remainder gives 11 minus the remainder. It's the same modulo-11 logic the CPF Generator uses for Brazil, just with a different letter-conversion table.