Free RFC Calculator with Homoclave Online (Mexico 2026)
Estimate your RFC with homoclave from your name and birth date, using the SAT’s public algorithm. Also for companies (personas morales).
Estimate your RFC with homoclave for individuals or companies using the SAT public algorithm. For reference only — the official RFC is issued by SAT.
By VOV · Last updated: October 21, 2026
Estimate using the public algorithm released by the IFAI. Only the SAT assigns the official RFC, which may differ (especially the homoclave) if there was a collision with another person. Your data never leaves your browser.
Use cases
- Get your RFC with homoclave to register with Mexico's SAT and start invoicing as a freelancer
- Calculate your new company's RFC before you register it and open the business bank account
- Verify a supplier's RFC matches their tax details before sending them a large wire transfer
Frequently asked questions
Is the RFC from this tool valid?
It is an estimate using the public algorithm released by the IFAI. Only the SAT assigns the official RFC, which may differ — especially the homoclave — if there was a collision with another person. For any procedure, use the RFC on your Constancia de Situación Fiscal.
How is an individual’s RFC formed?
4 letters (first letter and first inner vowel of the paternal surname, maternal initial and given-name initial), 6 birth-date digits (YYMMDD) and a 3-character homoclave with check digit.
What is the homoclave?
The last 3 characters of the RFC: two alphanumeric characters computed from your full name plus a check digit. They prevent duplicates when two people share a name and birth date.
Is my data stored or sent?
No. All computation happens in your browser; your name and date never leave your device.