Netherlands BSN validator
How the BSN format works
- Format
- 9 digits
- Example
- 111222333
Things to watch for
- 9 digits validated with the Dutch "11-proef" (11-test): a weighted sum over all 9 digits must be a multiple of 11
- Checksum only — we never store what you enter, and a number passing this test does not confirm it is currently issued to anyone
- All-zero input (000000000) always fails, even though it satisfies the mod-11 arithmetic
^[0-9]{9}$A BSN (Burgerservicenummer) is the Netherlands’ 9-digit citizen service number, assigned to everyone registered in the Basisregistratie Personen (BRP) — Dutch citizens and long-term residents alike. It’s the number tied to your employer, health insurer, DigiD login, and tax return; nearly every government-facing form in the country asks for it.
Unlike some national ID numbers, a BSN doesn’t encode a birth date or gender — structurally it’s closer to a plain serial, with one built-in safeguard: the “11-proef” (11-test). Each of the 9 digits is multiplied by a fixed weight — 9 down to 2 for the first eight digits, and -1 for the last — and the total must divide evenly by 11. That single arithmetic rule is what a mistyped or transposed digit almost always breaks.
How this validator works
This tool checks that the input is 9 digits and reruns the same weighted 11-test calculation against them, entirely in your browser — nothing you enter is transmitted or stored. It also rejects an all-zero input (000000000), which technically satisfies the mod-11 arithmetic but is never a valid BSN.
What a pass doesn’t tell you
Passing the 11-test confirms the 9 digits are internally consistent — not that the BSN was ever assigned to a real person or is currently active in the BRP. Only the Netherlands’ own population register can confirm a specific BSN is genuinely on file.
Scope: this page covers BSN format and 11-test validation only — not identity or residency verification. Because a BSN is sensitive personal data, treat a pass as a typo-check, not proof of anything about the person behind it.
Content last reviewed 2026-07-23.
BSN FAQ
What is a BSN and who is assigned one?
The Burgerservicenummer is the Netherlands' unique citizen service number, issued to everyone entered in the Basisregistratie Personen (BRP) — Dutch citizens and long-term residents alike. It's used with employers, health insurers, DigiD, and the tax authority.
How does the 11-test (elfproef) catch a mistyped BSN?
Each of the 9 digits is multiplied by a fixed weight — 9 down to 2 for the first eight, then -1 for the last — and the results are summed. A genuine BSN's total always divides evenly by 11, so a single wrong or swapped digit almost always breaks that.
Does a valid 11-test mean the BSN is genuinely registered?
No. It only confirms the 9 digits are mathematically consistent with each other — not that the number was ever issued or is currently active. Confirming registration requires access to the Netherlands' population register, which this client-side tool doesn't query.