The glossary to understand and take action

National identification number — 13-digit identification number

The national identification number of a natural person in Luxembourg comprises 13 digits and enables identification in the relevant procedures.

Notion comptable, fiscale ou juridique · Luxembourg Fiduciaries Editorial Team · Reviewed on

Understand the scope

Definition and points to distinguish

It should not be confused with company identifiers, the RCS number or the VAT number. This personal number must be provided only to an authorised recipient via an appropriate channel.

In your file

What this changes in practice

The national identification number is used to identify a person or an entity in specific administrative exchanges. It should not be confused with the RCS number, the VAT number or an identifier specific to a service provider. Before completing a form, check which identifier is requested and whom it relates to. Personal identifiers must be shared in an appropriate and secure setting.

A scenario to help you understand

Educational example

To declare an employee, the employer uses the identifier requested by the social security body and does not replace it with its company’s VAT number.

Fictitious situation, presented to illustrate the concept.

Prepare for what comes next

Points to check

  • Lire le libellé exact du formulaire
  • Identifier la personne ou l’entité concernée
  • Limiter la diffusion des identifiants

The practical question

Find out more

Pourquoi éviter de mélanger les identifiants dans les fichiers internes ?

Le matricule, le numéro RCS et le numéro de TVA répondent à des usages différents. Un champ unique intitulé numéro d’entreprise peut provoquer des erreurs dans les formulaires et exports. Nommez les champs précisément et vérifiez leur destinataire. Pour les identifiants personnels, limitez les accès aux personnes qui en ont besoin dans leur mission.

Connecting concepts

Terms to know as well

Continue with the concepts, contacts and procedures related to this topic.

VAT numberThe VAT number identifies a person for their value added tax obligations within the relevant system.RCSThe Trade and Companies Register (RCS), managed by Luxembourg Business Registers, centralises registrations and filings for the persons and entities concerned.Data minimisationA principle consisting of limiting the personal data used to what is necessary for the intended purpose.Social minimum wageThe social minimum wage is a statutory remuneration benchmark whose applicable amount varies, in particular, according to age, qualification and period.Wage indexationIndexation adjusts remuneration according to the legal mechanism of the sliding scale and the corresponding effective dates.Joint Social Security Centre (CCSS)The Joint Social Security Centre (CCSS) notably manages registrations and the collection of social security contributions within its remit.

Put it into practice

Explore further with our guides

Practical guideSocial minimum wage and indexation: check payroll parameters

Sources and verification

References consulted on 20 September 2026. Official procedures specify the applicable conditions and exceptions.

This guide explains a general process. The applicable rules depend on your situation; it does not constitute personalised advice. Report a correction.

A definition gives you a reference point. To examine your situation, clarify your question with a professional.