VAT id, KVK number and ob-nummer: what is the difference?
Updated on 3 August 2026 · 3 min read
Shortly after registering a business in the Netherlands you receive three numbers that look alike but serve different purposes. Two go on everything you publish; one you share with no one except the tax authority. Here is the difference in one table.
| Number | Issued by | Where you use it |
|---|---|---|
| KVK number | Chamber of Commerce (KVK) | Invoices, quotes, contracts, website |
| VAT id (btw-id) | Belastingdienst | Invoices, website, towards clients and suppliers |
| Turnover tax number (ob-nummer) | Belastingdienst | Only in contact with the Belastingdienst |
The three numbers in short
Your KVK number (8 digits) comes with your registration at the Chamber of Commerce. It identifies your business in the trade register and never changes.
Your VAT id (NL + 9 digits + B + 2 digits, like NL123456789B01) arrives by post from the tax authority shortly after your KVK registration. For sole proprietors it is a separate number that does not contain your citizen service number (BSN), so it is safe, and mandatory, to publish.
Your turnover tax number (ob-nummer) is the number the tax authority uses internally for your VAT; for sole proprietors it is based on your BSN. That is why it should never appear in public.
Which number goes where?
- On your invoice: your VAT id and your KVK number. Both mandatory.
- On your website: your VAT id (mandatory when selling to consumers), usually your KVK number too.
- On quotes and contracts: your KVK number.
- On your VAT return and letters to the tax authority: your ob-nummer. That is the only place.
Where do they sit on the invoice?
In the block with your business details: name, address, KVK number, VAT id, IBAN. Miss one and the invoice does not meet the Dutch invoice requirements.
How Finq handles it
In Finq you enter your KVK number and VAT id once, under Settings; from then on they appear on every invoice and quote automatically. Need a one-off invoice right now? The free invoice tool puts them in the right place too.