TN 1 (03-97)
The Belgian social insurance number consists of 8 or 9 digits which are assigned as
Digits 1-2 represent the year of birth;
Digits 3-4 represent the month of birth;
Digits 5-9 are chronologically assigned.
The Belgian social insurance number is used to control retirement and survivor claims.
The social insurance number is not used for invalidity claims. A separate number is
assigned for these claims. If the disabled person dies, the survivor claim is controlled
under the widow's own social insurance number.