How does the BSN elfproef work?

The 9 digits are multiplied by weights 9, 8, 7, 6, 5, 4, 3, 2 and the last by -1, then summed. The BSN is valid when that sum is non-zero and divisible by 11. Eight-digit BSNs are first padded with a leading zero. This tool implements that exact rule.

The Burgerservicenummer (BSN) is the Dutch citizen service number — a unique personal identifier used for tax, healthcare, benefits and other government dealings in the Netherlands. It is 8 or 9 digits long.

Why does an 8-digit BSN get a leading zero?

Older BSNs are 8 digits. The elfproef is defined over 9 positions, so an 8-digit number is left-padded with a zero to make 9 digits before the weighted sum is calculated.

What does it mean if my BSN fails the 11-test?

A failure means the digits do not satisfy the checksum, so the number is not a structurally valid BSN — usually a typo, a transposed digit or an invented number. Re-check the digits against your official document.

Does a valid BSN mean it belongs to a real person?

No. Passing the 11-test means the number is mathematically well-formed. It cannot confirm the BSN is issued or linked to anyone — only the Dutch government holds that record.

Can this tool generate a BSN?

No, and it should not be used to invent identity numbers. It only checks whether a number you already have is correctly formed. Using a fabricated BSN to impersonate someone is illegal.

Is my BSN sent anywhere?

No. The check runs entirely in your browser. Your BSN never leaves your device and there are no network requests.

Netherlands BSN Validator (Burgerservicenummer)

The Burgerservicenummer (BSN) is the Dutch citizen service number, used across tax, healthcare and government services in the Netherlands. This validator checks whether an 8- or 9-digit BSN is structurally correct using the official elfproef (eleven-test) checksum — entirely in your browser.

How it works

The BSN is normalised to 9 digits (an 8-digit number is left-padded with a leading zero). Each digit is multiplied by a fixed weight, with the final digit weighted -1:

sum = d₁×9 + d₂×8 + d₃×7 + d₄×6 + d₅×5 + d₆×4 + d₇×3 + d₈×2 + d₉×(-1)

The BSN is valid when that weighted sum is non-zero and divisible by 11.

Example

Take the test number 111222333:

Digit	1	1	1	2	2	2	3	3	3
Weight	9	8	7	6	5	4	3	2	-1
Product	9	8	7	12	10	8	9	6	-3

The products sum to 66, which is non-zero and exactly divisible by 11 (66 ÷ 11 = 6), so this number passes the elfproef.

Privacy-first: your BSN is processed entirely in your browser — nothing is uploaded or sent anywhere. The tool validates the documented format only and does not query any government database.