Belgian NRN Generator

What is a Belgian NRN?

The Belgian National Register Number, also used as the NISS social security number, is an 11-digit identifier for people registered in Belgium. Its structure encodes the date of birth, a sequence number and a two-digit checksum, so its format can be validated without any lookup.

NRN structure

YY.MM.DD-XXX.CC

YY.MM.DD

date of birth

XXX

sequence number: odd for men, even for women

CC

checksum: 97 minus the first nine digits modulo 97

For people born in 2000 or later, the checksum is calculated with a 2 placed in front of the first nine digits, so it differs from pre-2000 numbers.

Special cases. When the date of birth is unknown or incomplete, the month and/or day can be 00. People not entered in the National Register, such as cross-border workers, receive a BIS number instead: 20 is added to the birth month if their gender was known when the number was assigned, or 40 if it was not.

Test data only

BeNRN generates synthetic numbers for development and testing. They follow the official format and checksum, but a generated number may coincidentally match a real one, so never assume it does or does not belong to a real person, and never use it in production data.