CPF Check Digit Calculation

CPF Check Digit Calculation

We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

The Individual Taxpayer Register (CPF), issued by the IRS, is characterized by a function between the set of registered individuals and the set of issued documents.

That is, the fact that a CPF number is authenticated by its verifying digits does not make it a valid CPF because it must be registered in the IRS database. Thus, a valid social security number will not always be a document already issued. However, the check digits serve to alert you that the number was spelled improperly without having to access the IRS database.

Practical Rule

A CPF number is 9 digits plus two double-digit digits, which are indicated after a slash. Therefore, a CPF has 11 digits. The CPF number is written in the form ABCDEFGHI / JK or directly as ABCDEFGHIJK, where the digits can't all be the same each other.

O J is called 1st check digit CPF number.

O K is called 2nd check digit CPF number.

First Digit

To get J we multiply A, B, C, D, E, F, G, H and I by the corresponding constants:


The sum result, 10A + 9B + 8C + 7D + 6E + 5F + 4G + 3H + 2I, is divided by 11.

We then analyzed the REST of this division:

If it is 0 or 1, the digit J is 0 (zero). If it's 2, 3, 4, 5, 6, 7, 8, 9, or 10, the digit J it's 11 - REST

Second Digit

We already have J. To get K multiply A, B, C, D, E, F, G, H, I and J by the corresponding constants:


The sum result, 11A + 10B + 9C + 8D + 7E + 6F + 5G + 4H + 3I + 2J, is divided by 11.

We then checked the REST of this division:

If it is 0 or 1, the digit K is 0 (zero). If it's 2, 3, 4, 5, 6, 7, 8, 9, or 10, the digit K It's 11 - REST.


  1. Beartlaidh

    I am here by chance, but I specially registered to participate in the discussion.

  2. Imre

    Excuse, that I interfere, but, in my opinion, there is other way of the decision of a question.

  3. Ruark

    Congratulations, you just visited another idea

  4. Dunleah

    This is no longer an exception.

  5. Kaori

    I think you are making a mistake. Let's discuss this. Email me at PM.

  6. Amr

    Whimper! It gives an error ... Right now I will be nervous ...

  7. Incendio

    In my opinion it is obvious. I advise to you to try to look in

Write a message