A BSN is a 9‑digit number assigned by the Dutch tax authority. The last digit is a checksum calculated with the “11‑proef” algorithm. Enter a number and this BSN Checker will instantly tell you if the format and checksum are valid.
Valid examples: 123456782, 111222333, 999991234.
The BSN (Burgerservicenummer) is the Dutch citizen service number – a unique personal identification code issued by the Dutch tax authority (Belastingdienst) to every natural person registered with the government, including residents, expats, and temporary workers. This 9‑digit number is used for taxes, healthcare, education, social benefits, and virtually all official matters. The BSN follows the “11‑proef” (11‑test) algorithm: the sum of each digit multiplied by a specific weight must be divisible by 11. For example, 123456782 is a valid BSN.
Three simple steps to verify any BSN:
You can try the sample numbers to see how the BSN Checker works. If you enter an invalid number (wrong length, letters, or failing checksum), you’ll get a clear error message.
This BSN Checker is completely free and requires no sign‑up. It’s ideal for residents, HR departments, government agencies, and financial professionals.
No. This BSN Checker only validates the format and 11‑proef algorithm. A “valid” result means the number is structurally correct. To confirm whether it has been officially assigned, is currently active, or belongs to a specific person, you must consult official Dutch registers (e.g., the tax authority or municipal records). This tool does not store or verify personal identity data.
Common reasons: length is not exactly 9 digits, contains non‑numeric characters, or the 11‑proef checksum fails. For BSN 123456782, the calculation is (1×9 + 2×8 + 3×7 + 4×6 + 5×5 + 6×4 + 7×3 + 8×2 + 2×1), and the total must be divisible by 11. Double‑check your input, or test with the provided examples to ensure the BSN Checker is working correctly.
This page is designed for single checks. For batch processing, you can integrate via our API endpoint /iso-checker with parameters type=bsn&number=your_number. Contact us if you have questions.
Yes. Anyone legally staying in the Netherlands for more than 4 months, or foreign nationals with a Dutch employment contract, must register at the municipal BRP and receive a BSN for tax and social security purposes.
Absolutely – no charges, no hidden fees. OkeyTool provides useful online utilities for everyday needs.
If you have further questions or encounter any issues, please reach out via the contact information at the bottom of the site. Thank you for using our BSN Checker!