A typing mistake in an RFC or a CURP can get an invoice or an application rejected. Before submitting them, you can check that they're written correctly.
How the RFC is formed
- Individual (13 characters): 4 letters from the name, date of birth (YYMMDD) and 3 characters of homoclave.
- Company (12 characters): 3 letters, date of incorporation and homoclave.
- The last character is a check digit calculated from the previous ones.
With Validate RFC Format you type the RFC and the tool checks the format, that the date exists and that the check digit matches. It also recognizes generic RFCs (general public and foreigners).
How the CURP is formed
The CURP has 18 characters: 4 letters from the name, date of birth, sex, state of birth, 3 internal consonants, a homoclave character and a check digit. Validate CURP Format checks that structure and shows you the date, sex and state it encodes.
What they do and don't check
They do: check for formatting errors, an impossible date or a digit that doesn't add up, which are usually typing mistakes.
They don't: check that the RFC or CURP exists, is current or belongs to a person. For that you need the official lookup from the SAT or gob.mx. The tools run in your browser and what you type isn't sent to any server.
Other tools for paperwork
- Number to words (Spanish): the amount in words for checks, promissory notes and receipts.
- Passport and Visa Photo: the right size for your photos.
- QR code generator: to share links or contact details.
One last tip: never share your CURP, your RFC or your documents on sites you don't know. Read this guide on privacy.