sofinummer

Sofinummer, short for sociaal-fiscaal nummer, is the Dutch national personal identification number historically used to identify individuals for social security and taxation. It was issued by Dutch authorities and used across government systems to link records in the social insurance and tax domains.

With the introduction and gradual adoption of the Burgerservicenummer (BSN) and the Basisregistratie Personen (BRP), the BSN became the standard identifier in most official contexts. The transition means that today the BSN is the primary identifier used by government bodies, while the sofinummer is largely a legacy identifier found in older records, historical datasets, and some archival documents.

Format-wise, the sofinummer is a nine-digit numeric code, similar in appearance to the BSN. In current practice it is not used for new registrations or modern administrative processes; the BSN is the active national identifier for residents and citizens interacting with public institutions.

Privacy and security considerations apply to both numbers, as they are linked to sensitive personal data such as tax and social security information. Because the sofinummer is a legacy identifier, handling and sharing it today should be approached with caution, and where possible the BSN should be used in contemporary government interactions.

In summary, the sofinummer was historically used to identify individuals for social security and tax purposes in the Netherlands but has been largely superseded by the Burgerservicenummer. It remains relevant mainly for reference in older documents and historical records.