Invoice rules are set out in the Dutch Turnover Tax Act (Article 35a). A correct invoice is required for your VAT return and your client's input VAT deduction.
Mandatory invoice fields (12)
Invoice date
The date you issue the invoice.
Invoice number
Unique sequential number without gaps.
Your name and address
Full legal name and business address.
KvK number
Required for companies registered in the Netherlands.
VAT number (BTW/OB)
Required if you are VAT-registered.
Customer name and address
Full client details.
Description of service/product
What you delivered (date, hours, rate).
Amount excluding VAT
Net price per line and total.
VAT rate and VAT amount
Usually 21%, sometimes 9% or 0%.
Total amount including VAT
Final amount the customer pays.
Payment term or due date
Often 30 days — state a specific date.
Bank account (IBAN)
Business IBAN; add BIC for international clients.
Highly recommended (not mandatory)
Customer reference
For your client's internal admin.
Purchase order number (PO)
Often required by larger organisations.
Payment reference
Makes bank reconciliation easier.
KOR mention
Under KOR: «VAT exempt under the KOR scheme».
Example invoice header
INVOICE Invoice number: 2026-001 Invoice date: 26 June 2026 Due date: 26 July 2026 From: Jan de Vries | Freelance Design Keizersgracht 123, 1015 CJ Amsterdam KvK: 87654321 | VAT: NL123456789B01 IBAN: NL91 ABNA 0417 1643 00 To: Acme B.V. | Herengracht 456, 1017 BZ Amsterdam KvK: 12345678 Description: Web design project Q2 2026 — 40 hours @ €95 Amount excl. VAT: €3,800.00 VAT 21%: €798.00 Total incl. VAT: €4,598.00
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