RFC Validator
ValidatorValidate Mexican RFC tax identification numbers. Supports personal (13 chars) and business (12 chars) RFC formats. Format validation with date decoding. Runs entirely in your browser.
RFC (Registro Federal de Contribuyentes) is Mexico's federal taxpayer registration number issued by the SAT. Every individual and legal entity performing economic activities in Mexico must have an RFC. It appears on invoices (CFDI), payroll records, bank accounts, and tax filings.
| Type | Length | Structure | Example |
|---|---|---|---|
| Personal RFC | 13 | 4 letters + YYMMDD + 3 chars | GOLA871120ABC |
| Business RFC | 12 | 3 letters + YYMMDD + 3 chars | GAL871120XY3 |
About this tool
About RFC Validator
This validator checks Mexican RFC (Registro Federal de Contribuyentes) numbers for correct format and structure. It auto-detects whether the RFC is personal (13 chars) or business (12 chars), validates the character patterns for each segment, checks that the date portion is a valid date, and returns decoded components. Note: the RFC homoclave is an internal SAT code that cannot be verified without SAT database access — this tool validates format only.
The validator accepts both personal and business RFC formats, strips spaces and hyphens before checking, and reports specific error messages for each failure mode. On a valid RFC it decodes the name code, the date (with century estimation), and the homoclave.
Use this validator to verify RFCs collected from users before invoicing (CFDI), to debug RFC validation failures in SAT integrations, to check if a manually entered RFC matches the expected format, or to test RFC generation logic.
Instant format validation with no network requests. The validator distinguishes between personal and business RFC formats automatically and provides clear error messages for each failure mode.
Key Features
- Validates both personal (13 chars) and business (12 chars) RFC
- Auto-detects RFC type from length
- Date portion validation (YYMMDD)
- Decodes name code, date, and homoclave
- Century estimation (YY < 30 → 2000s, else → 1900s)
- 100% browser-based, no SAT database access
FAQ
RFC Validator — Frequently Asked Questions
What is an RFC and why do I need to validate it?
RFC (Registro Federal de Contribuyentes) is Mexico's federal taxpayer ID. It appears on all invoices (CFDI), payroll documents, bank records, and tax filings. Validating the RFC format before submitting to the SAT saves errors and prevents invoice rejection — an incorrectly formatted RFC causes a CFDI to be rejected outright.
Does this validator check with the SAT database?
No. This tool performs format validation only — it checks that the RFC has the correct length, character pattern, and a valid date in the date portion. To verify that an RFC is actually registered with the SAT, you would need to query the SAT's official LCO (Lista de Contribuyentes Obligados) service or use the SAT's online RFC query.
What does each part of the RFC mean?
Personal RFC: positions 1–4 are derived from the person's names (same rules as CURP names); positions 5–10 are the birth date in YYMMDD; positions 11–13 are the SAT-assigned homoclave. Business RFC: positions 1–3 from company name; positions 4–9 are constitution date YYMMDD; positions 10–12 are the homoclave.
Why does century detection use YY < 30 → 2000s?
Since the RFC only stores two digits of the year, the validator uses a heuristic: YY < 30 maps to 2000–2029, YY ≥ 30 maps to 1930–1999. This covers the vast majority of active taxpayers. For edge cases born in exactly 1930 or 2030, the full context (personal vs. business, field type) determines the correct interpretation.
Tips
- The RFC is all-uppercase — the validator normalises lowercase input automatically
- Business RFCs are 12 characters; personal RFCs are 13 — a wrong length is the most common error
- The RFC validator checks format only; use the SAT portal to verify registration status
- Compare the RFC Validator output against the CURP Validator for cross-referencing person data