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
When should you send the invoice?
As a rule you issue an invoice for a supply to another business no later than the fifteenth day of the month after the supply. Don't wait too long: a prompt invoice means quicker payment and tidy records.
Made a mistake? Correct it with a credit note
You don't quietly edit a sent invoice. Issue a credit note that cancels the original invoice and send a new, correct one. That keeps your numbering consistent and your VAT return accurate.
Special situations
Clients abroad, VAT reverse charge or the KOR bring additional rules and statements on your invoice. Check them before sending, and ask your accountant or the Tax Authority when in doubt.
Frequently asked questions
Does an invoice have to be a PDF?
No, an invoice can be digital in another format as long as authenticity and legibility are assured and the client agrees. A PDF is the most common.
How long do I keep my invoices?
As a rule seven years. For certain items a longer period may apply; ask your accountant if in doubt.
May I send an invoice in English?
Yes, but make sure all mandatory details are on it and the client understands the content. State a Dutch VAT reverse charge clearly.
What is a good payment term?
14 or 30 days are common. Agree the term in advance, put the due date on the invoice and use a reminder for late payers.
Create invoices with the fields SmartWerk checks
SmartWerk fills supported invoice fields from your profile and checks formats. That does not guarantee every invoice is legally correct in every situation.
Start free →