Short answer
The RFC (Registro Federal de Contribuyentes) is Mexico’s taxpayer ID, issued by the SAT: 12 characters for a company and 13 for an individual. It is the most reliable key for matching a supplier across records, yet neither INEGI’s DENUE nor the IMMEX directory publishes it, so a buyer has to ask the supplier for it.
Key facts
- Company RFC
- 12 characters: 3 letters from the name, 6 digits for the date, 3 for the homoclave
- Individual RFC
- 13 characters: 4 letters, 6 digits for the date, 3 for the homoclave
- In DENUE and the IMMEX directory
- Not published (files read 25 Sep 2026)
What an RFC looks like
| Taxpayer | Length | Structure |
|---|---|---|
| Company (persona moral) | 12 characters | Three letters from the name, six digits for the date of constitution, three characters of homoclave assigned by the SAT |
| Individual (persona física) | 13 characters | Four letters from the name, six digits for the date of birth, three characters of homoclave |
The structure tells you whether a number could belong to a company or a person. It does not tell you the number is real or current. Only the SAT can confirm that.
Where a buyer sees the RFC
- On every Mexican electronic invoice (CFDI), which states the issuer’s RFC and legal name.
- On the supplier’s Constancia de Situación Fiscal, the SAT document that shows the RFC, the legal name and the registered tax address.
- In the SAT’s Article 69-B list, which includes the RFC of every listed taxpayer.
How to check a supplier’s RFC
- Ask for three thingsThe RFC, the legal name as registered and a recent Constancia de Situación Fiscal.
- Compare the three with your paperworkThe name and RFC on the quote, the purchase order and the invoice should match the Constancia exactly.
- Search the 69-B list by RFCAn RFC search is more reliable than a name search. See the 69-B guide for the statuses.
- Match to the registries by name and postal codeBecause DENUE and the IMMEX directory carry no RFC, match by legal name and postal code and note the method used.
Why public registries leave it out
The DENUE bulk files and the IMMEX directory that Testigo downloaded on 25 September 2026 contain no RFC column. Testigo therefore matches plants to the IMMEX directory on exact name and postal code, and every record states which method produced the match. When a supplier hands over its RFC, that is the strongest link you can add.
Many third-party websites offer an RFC lookup. Check what each one reads and when; a lookup that does not name its source and date is a guess. Testigo does not run an RFC lookup.
Frequently asked questions
How long is a Mexican RFC?
A Mexican RFC has 12 characters for a company and 13 for an individual. Both end with a three-character homoclave assigned by the SAT. The letters come from the name and the six digits from the date of constitution or birth, so the structure tells you which kind of taxpayer a number claims to be.
Can I look up a Mexican company’s RFC by name?
Not reliably from public registries. INEGI’s DENUE and the IMMEX directory do not publish the RFC. Ask the supplier for its Constancia de Situación Fiscal and compare the name and RFC with your paperwork. Be cautious with third-party lookup sites that do not state their source and date.
What is a Constancia de Situación Fiscal?
A Constancia de Situación Fiscal is the SAT document that shows a taxpayer’s RFC, legal name and registered tax address. A supplier can obtain it from the SAT and share it. Compare it with the name on your quote and invoice before you place an order.
Does Testigo publish RFCs?
No. Testigo records do not include an RFC because no public source gives it, and the record says so. We match plants by exact name and postal code and state the method. We never show a possible 69-B match publicly; a person reviews it first.