Check a Dutch BSN (Burgerservicenummer) via the 11-proef checksum - entirely locally in your browser, no upload.
Running locally on your device ...
Running locally on your device ...
0%
Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
The BSN (Burgerservicenummer) is the Dutch 9-digit citizen service number. Its checksum is called the "11-proef" (11-test): the first 8 digits are multiplied by weights 9 through 2, the 9th digit is subtracted, and the sum must be divisible by 11 (including 0). This tool computes exactly that.
Paste the number (spaces and dots are ignored) and you get an instant result: valid or invalid, with the computed weighted sum shown for transparency.
The whole check runs locally in your browser in pure JavaScript - the entered number is not uploaded, not stored, and no foreign library is loaded from a CDN. The BSN is treated as a specially protected personal data item under Dutch law (UAVG); this tool processes it only in your device's memory.
| Input formats | Text input |
|---|---|
| Output format | TXT |
| Batch processing | No |
| Processing | Locally in your browser (JavaScript) |
| File upload | None |
Limitations: This tool performs only a mathematical checksum/format check. It is not an official identity, existence, or registry verification and not a request to any authority. Any additional information derived from the number's structure is based solely on the publicly documented encoding logic of the issuing authority.
No. The check runs entirely locally in your browser; the number never leaves your device and is not stored.
A weighted checksum over all 9 BSN digits: the first 8 digits are multiplied by 9 through 2, the 9th is subtracted, and the sum must divide evenly by 11.
Yes, the field is a 9-digit string, not a number - a leading zero is handled correctly.
No. It only checks the mathematical checksum - no query against a Dutch authority or registry.
Yes. After the first load, the check works entirely without an internet connection.
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