If you have ever been on a Mexican payroll or dealt with SAT, Mexico’s tax authority, you already have an RFC (your tax ID), even if you can’t remember it. You can recover it for free, without a password. The fastest place to look is an old payslip. If you don’t have one, SAT will send it to you with nothing more than your INE voter card, online or at an office with no appointment.
Pick the route that fits what you have
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If you have a payslip
Look there: it takes a minuteEvery stamped Mexican payslip shows your full RFC in the employee details.
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If you only have your INE
Request it through SAT IDSAT emails you your tax status certificate, and your RFC is on it.
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If you’d rather go in person
Visit a SAT officeNo appointment is needed for the certificate. You leave with your RFC printed.
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If you work for a company
Ask HRYour employer uses your RFC on every payroll run and can look it up with SAT.
What an RFC looks like (and why the homoclave matters)
An individual’s RFC has 13 characters. Here is a fictional example for “Ana Ruiz Pérez,” born on August 5, 1992:
920805
8Q3
- RUPA: letters from your surnames and first name.
- 920805: your date of birth (year, month, day).
- 8Q3: the homoclave, assigned by SAT to tell apart people with similar details.
The first 10 characters almost always match the start of your CURP, Mexico’s population ID code; here’s how to look up your CURP for free. That’s why online calculators get that part right. Only SAT knows your homoclave.
If a wrong homoclave goes on your payroll registration or an invoice, that document ends up under someone else’s RFC, and fixing it later takes far longer than finding the right one today.
1. Check a payslip
If you have ever been paid through a Mexican payroll, you have stamped payslips (called CFDI de nómina), and each one shows your full RFC in the employee or recipient section. Check your email, since many employers send them as PDF and XML files, or your company’s employee portal.
No payslips? Your RFC also appears on any invoice issued in your name, on an earlier tax status certificate (the RFC never changes), or on the receipt you got if you ever registered in person.
2. No password: request it through SAT ID with your INE
SAT ID is SAT’s online service for people with no password and no e.firma (SAT’s electronic signature). It doesn’t give you the RFC on its own: it sends you your Constancia de Situación Fiscal (tax status certificate), and your RFC with homoclave is on the first line.
- Make sure your INE voter card is valid using the INE voter list lookup. An expired card is the most common reason requests are rejected.
- Go to satid.sat.gob.mx and choose Constancia de Situación Fiscal con CIF.
- Follow the steps: your details, an email address, photos of your original INE card and a short video to confirm it’s you.
- If SAT approves your request, the certificate arrives as a PDF by email. Your RFC is at the top.
Photograph your INE in good light, with no glare and no cropped edges, and record the video facing the camera with your whole face visible. If you’re rejected, you can try again after fixing what failed.
Official requirements: you must be an adult, a Mexican national, and hold a valid INE voter card, whether issued in Mexico or abroad.
3. At a SAT office, no appointment needed
If you’d rather sort it out in person, collecting the certificate at a SAT office doesn’t require an appointment. Bring a valid official photo ID; if you have an e.firma, your fingerprint is enough. You’ll leave with the printed certificate, and with it your RFC.
4. Ask your employer
If you currently work for a company, this is the easiest route. HR uses your RFC every payday, so they have it on file. SAT also runs a service that lets employers look up their workers’ RFCs, and if your employer registered you when you were hired, they had to do so by the end of the following month.
What if you’ve never registered?
If you have never been on a payroll, never issued an invoice and never dealt with SAT, you most likely don’t have an RFC yet. There’s nothing to recover: you need to register, which is a separate procedure that requires an appointment.
If your RFC is wrong
It happens more often than you’d think: an employer registered you with a different homoclave, or you corrected your CURP and your RFC no longer matches. SAT lets you request an RFC change in two situations:
- You’re a salaried employee and have used a different code with SAT or Mexico’s social security system in the last five years, or the code you were given doesn’t match your details.
- You corrected your CURP and your RFC is now out of sync. No documents are needed, only being up to date with SAT.
You file it online with your password in SAT’s “Mi portal,” choosing the “Cambio de RFC” procedure. SAT responds within 20 days.
Frequently asked questions
How much does it cost to find my RFC?
Nothing. Every official route in this guide is free. If a website charges you to “give you your RFC,” it isn’t SAT.
Can I find my RFC with just my CURP?
Your CURP gives you the first 10 characters, which almost always match. The homoclave, the last 3, only comes from SAT, which is why the certificate via SAT ID or at an office is the reliable route.
Does my RFC change over time?
No. It stays the same for life, unless it’s corrected because of an error, for example after a CURP correction.
Can I look up someone else’s RFC?
No. For privacy reasons there is no public SAT search by name. Each person gets their own with their own ID or password.
How many characters does an RFC have?
13 for individuals: four letters, six digits for your date of birth and a three-character homoclave.
Reviewed on September 25, 2026 by Nadir Yaqoob, based on SAT’s official procedure sheets published in the Diario Oficial de la Federación (Annex 2 of the 2026 Miscellaneous Tax Resolution, in Spanish).
