Belgian National Number / INSZ Generator

For test data, not identities

This generator creates structurally valid synthetic test numbers: the date, sequence parity and modulo-97 control digits follow the Belgian format. It does not query the National Register or BIS register and cannot tell whether a generated value has ever been assigned. For that reason the default date is in 2099.

Rijksregisternummer and INSZ/NISS

An INSZ/NISS is either a National Register number or a BIS number. A National Register number uses YYMMDD-SSS-CC; the three-digit sequence is odd for male and even for female records. For births from 2000 onward, the checksum is calculated after prefixing the first nine digits with 2.

BIS numbers use a month offset of 40 when sex was known at creation and 20 when it was unknown. This tool can generate both variants for integration tests. The official KSZ/BCSS documentation remains the authority for production validation.

Privacy

Generation happens entirely in the browser. No birth dates or generated numbers are sent to gratistools.be. Do not use generated values to impersonate a person or as evidence that an identifier exists.