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People and places

Form Z-09

Check a national register number

Check whether a national register number or BIS number is well formed. This happens only on your own device: the number goes nowhere.

Checked on your device

Explanation

Check a national register number in three steps

  1. Type the number

    Eleven digits, with or without dots and a dash, as on the back of an identity card.

  2. Zegel does the maths

    The check digits and, for people born in 2000 or later, the 2 that goes in front.

  3. Read the result

    The date of birth, whether it’s a BIS number, and the sex as it appears in the number.

At the counter

Good to know

  • Does the number go to a server?

    No. The check happens in your browser. Zegel doesn’t send the number anywhere, doesn’t store it and doesn’t put it in the page address either.

  • What’s the rule for people born after 2000?

    The check digits are 97 minus the remainder of the first nine digits divided by 97. For people born in 2000 or later, you first put a 2 in front of those nine digits. That way the check digits reveal the century.

  • What is a BIS number?

    A number for people who aren’t in the national register, for example someone who works in Belgium but doesn’t live there. In that case 20 or 40 is added to the month.

Sources

What this tool relies on, with the date we checked it.

  1. GovernmentRijksregisterFOD Binnenlandse Zaken, Algemene Directie Instellingen en Bevolking · checked on 13 October 2026 · still to be reviewed

Texts reviewed on 21 October 2026

Zegel checks and calculates, but gives no legal or tax advice. If in doubt, ask your accountant or the relevant authority.

Spotted a mistake?

A few words are enough. We will check and fix it.

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