Home RFC (company) Mexico
Mexico RFC (company) validator
How the RFC (company) format works
- Format
- 12 characters: 3-letter/digit prefix + 6-digit incorporation date (YYMMDD) + 3-character homoclave, the last of which is a mod-11 check digit
- Example
- CFE370814QI0
Things to watch for
- This validates the 12-character company (persona moral) RFC only — the 13-character individual RFC embeds a person's name-derived letters and birth date (personal data) and is intentionally out of scope
- SAT's own systems don't strictly enforce a valid check digit in the wild — some real, in-use RFCs carry a check digit that doesn't match this formula, so a failure here doesn't always mean the RFC is fake
- Checksum only — a pass doesn't confirm the RFC is currently registered or active with SAT
^[A-ZÑ&]{3}[0-9]{6}[A-Z0-9]{3}$The RFC (Registro Federal de Contribuyentes) is the tax identifier Mexico’s SAT (Servicio de Administración Tributaria) assigns to every taxpayer — and it comes in two different lengths depending on who holds it. A company or other legal entity (persona moral) gets a 12-character RFC, for example CFE370814QI0; an individual (persona física) gets a 13-character RFC built from letters drawn from their name plus their birth date. This tool validates the 12-character company form only.
Reading the 12 characters
The first 3 characters are drawn from the company’s legal name, the next 6 digits are its incorporation date in YYMMDD format, and the final 3 characters are the homoclave — a code SAT assigns to distinguish entities that would otherwise produce an identical prefix and date. The last character of the homoclave is a check character, computed with a mod-11 calculation across the preceding 11 characters using SAT’s own character-to-value mapping (every digit and letter, plus a handful of special characters, has a defined position).
Why the individual RFC is out of scope
The 13-character persona física RFC embeds letters derived from a person’s actual name and their date of birth — personally identifiable information. This validator deliberately covers only the 12-character company form, and rejects anything of a different length rather than attempting to validate personal data.
An honest limit on this check
SAT’s own systems don’t strictly enforce a matching check character in practice, so some real, in-use company RFCs carry a homoclave whose last character doesn’t match this formula. A failed check here is a reason to double-check the number, not automatic proof it’s invalid, and a pass never confirms the RFC is currently active with SAT.
Scope: this page and tool cover the 12-character company (persona moral) RFC’s format and checksum only — not SAT registration status, and not the 13-character individual RFC.
Content last reviewed 2026-08-09.
RFC (company) FAQ
Why does Mexico have two different RFC lengths?
The RFC format differs by legal person type: a company or other legal entity (persona moral) gets a 12-character RFC, while an individual (persona física) gets a 13-character RFC that embeds letters from their name and their birth date. This tool validates the 12-character company form only.
What is the homoclave in an RFC?
It's the last 3 characters of a company RFC, assigned by SAT to distinguish entities that would otherwise share an identical name-prefix and incorporation date. The final character of the homoclave is a check character computed by a mod-11 formula over the preceding characters.
If a company RFC fails this checksum, is it definitely fake?
Not necessarily. SAT doesn't strictly enforce a matching check character across all its own real-world records, so a small share of genuinely active RFCs fail this formula. A failure is a reason to double-check the number, not proof by itself that it's invalid.