New ZZP'ers often confuse these three numbers. Here's what each one actually is, and which belongs on your invoices.
Last updated: June 2026
Your KvK-nummer is an 8-digit number issued by the Kamer van Koophandel (Dutch Chamber of Commerce) when you register your business — this is your general business registration, confirming your enterprise legally exists and is registered in the Dutch business register (Handelsregister). Every business operating in the Netherlands, including sole trader ZZP’ers, generally needs one.
Your BTW-id (VAT identification number) is a separate number specifically for VAT purposes, in the format NL followed by 9 digits, the letter B, and 2 more digits. This is the number you use on invoices, and the one your EU business customers verify via the VIES system to confirm your VAT-registered status for cross-border B2B transactions. Since 2020, sole traders’ BTW-id is deliberately structured to avoid directly exposing your personal citizen service number (BSN), which older VAT number formats used to reveal.
Your BTW-id is what appears on invoices you issue to customers, and what you use for OSS, IOSS, and cross-border VAT purposes. Your KvK-nummer appears on official business correspondence and is what other businesses use to look up your registration in the Handelsregister. Some Belastingdienst correspondence also references a separate BTW-nummer/RSIN used specifically for internal tax administration purposes, distinct from the public-facing BTW-id used on invoices.
Your BTW-id (VAT identification number) is what belongs on invoices, not your KvK-nummer, which is your general business registration number instead.
Yes, when you register with the KvK as a sole trader, your registration is generally passed to the Belastingdienst, which then issues your BTW-id and BTW-nummer.
The older format for sole traders directly incorporated your BSN (citizen service number), creating a privacy and identity-theft risk since VAT numbers are often publicly displayed. The newer NL+9digits+B+2digits format avoids this.
Your BTW-id — the EU’s VIES system is specifically for verifying VAT identification numbers, not general business chamber registration numbers like the KvK-nummer.
Generally yes, you’re still issued a BTW-id as part of registration, but if you’re exempt from charging BTW under KOR, you typically don’t display it as a charging VAT number on invoices in the same way — check current invoicing guidance for KOR participants.
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