How this works
A Portuguese NIF has nine digits and ends in a check digit. That digit comes from the first eight: multiply each by a weight from 9 down to 2, add them up, take the remainder of dividing by 11, then compute 11 minus that remainder (if it gives 10 or 11, the digit is 0). If it does not match the last digit, the number is wrong.
Frequently asked
What is the NIF check digit?
A NIF has 9 digits. The first 8 identify the taxpayer and the 9th is a check digit derived from the others (a modulo-11 formula). If the last digit does not match, the number is mistyped.
Does this tell me who a NIF belongs to?
No. The check is purely mathematical and runs in your browser — we query no database and not the tax authority. It only confirms the number is well-formed and shows the type (individual, company, etc.) from the first digit.
What does the first digit mean?
It marks the holder type: 1, 2 and 3 are individuals; 5 is a company; 6 is public administration; 45 is a non-resident; 70–79 and 90–99 cover estates, funds and other cases.
Is a formula-valid NIF a real one?
Not necessarily. Passing the formula only means it is well-built. It may exist, belong to someone else, or never have been issued. To confirm a real NIF use the tax authority’s official channels.
How do I get a NIF if I do not have one?
You can get it free at any tax office or Loja do Cidadão, or remotely via a fiscal representative. See the "How to get your NIF" guide here on howto.pt.
DISCLAIMER
This tool only checks the number’s mathematics and identifies the type from the first digit. It does not confirm whether a NIF exists, is active or who it belongs to, and is no substitute for an official check with the tax authority. Not tax advice.