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Netherlands btw-nummer validator
How the btw-nummer format works
- Format
- NL + 9 digits + B + 2 digits
- Example
- NL004495445B01
Things to watch for
- Includes a literal B before the final two digits
- Valid if either the first 9 digits pass the BSN check or the full 12 characters pass an ISO 7064 MOD 97,10 check (the newer sole-proprietor scheme only satisfies the second)
^NL[0-9]{9}B[0-9]{2}$A Dutch VAT number, the btw-nummer, has a shape unlike most EU formats: “NL”, then 9 digits, then a literal letter “B”, then 2 more digits — NL123456789B01. That embedded “B” isn’t a variable placeholder or a typo waiting to happen; it’s a fixed character every valid Dutch VAT number contains in that exact spot, right before the final two-digit segment.
The format has a real history worth knowing: until 2020, a sole trader’s VAT number (then called an omzetbelastingnummer) was built from their personal BSN — the Dutch citizen service number — which meant a private national ID was effectively printed on public invoices and websites. The Belastingdienst (Dutch Tax and Customs Administration) introduced a separate “btw-id” specifically for sole traders to stop that exposure, so older references to a Dutch VAT number and the current btw-id format aren’t always describing the same thing.
Checking the format
This validator confirms the “NL” prefix, counts exactly 9 digits, checks for the literal “B”, counts the final 2 digits, and then checks the number against either of the two valid check-digit schemes: the classic BSN “11-test” on the first 9 digits, or an ISO 7064 MOD 97,10 check over the full 12-character body (the scheme newer sole-proprietor btw-ids use) — entirely in your browser, no signup, nothing sent to a server. A pass means at least one of the two checks succeeds.
Not covered here
A pass confirms shape and a valid checksum, not that the number is a live, currently registered btw-id. Confirm current status through the EU’s VIES lookup or the Belastingdienst before relying on it for invoicing.
Scope: Dutch VAT number format and check-digit validation — not registration status.
Content last reviewed 2026-07-07.
btw-nummer FAQ
What does the letter B mean in a Dutch VAT number?
It's a literal, fixed character that always appears before the final two digits — for example NL123456789B01. It isn't a variable or an optional marker; every valid Dutch VAT number includes it in that exact position.
Why did the Netherlands change how sole traders' VAT numbers work?
Before 2020, a sole trader's VAT number (omzetbelastingnummer) was derived from their personal BSN citizen service number, which meant a personal ID was effectively visible on public invoices. The Dutch tax authority introduced a separate 'btw-id' for sole traders specifically to stop exposing that personal identifier.
Does a correctly formatted Dutch VAT number mean it's currently registered?
No — this tool checks format and the check digit (either the BSN 11-test on the legacy scheme, or an ISO 7064 MOD 97,10 check on the newer sole-proprietor btw-id), not live registration. Confirm live registration through the EU's VIES lookup or the Belastingdienst (Dutch Tax and Customs Administration) directly.