Creating an Invoice as a Freelancer (ZZP) 2026: Complete Guide with Legal Requirements

An invoice is the moment your work becomes revenue — and the moment the Belastingdienst expects everything to be legally correct. This 2026 guide walks Dutch freelancers through every mandatory data point, the VAT rules that apply to you, statutory payment terms, the rise of e-invoicing via Peppol/UBL, and the mistakes that trigger audits. Want to skip ahead and create one now? Use our free invoice generator.

Table of Contents

1. 1. Mandatory invoice data (factuureisen)
2. 2. Simplified invoices and KOR
3. 3. VAT rates and reverse charge
4. 4. Payment terms and statutory interest
5. 5. Invoice numbers, deadline and retention
6. 6. E-invoicing: Peppol, UBL and the 2030 deadline
7. 7. The 8 most common invoice mistakes
8. 8. Quick checklist before sending

1. Mandatory invoice data (factuureisen)

You are obligated to issue an invoice for every delivery to another entrepreneur or to a legal entity that is not an entrepreneur (such as an association or foundation). For sales to private consumers, an invoice is usually not required — although consumers often ask for one and you may need it for warranty disputes.

The Belastingdienst lists the following data as legally required on a regular invoice:

2. Simplified invoices and KOR

For invoices up to and including €100 (incl. VAT) you may use a simplified invoice. The same applies when you correct an earlier invoice (a credit note that refers to the original).

A simplified invoice must contain at minimum: the invoice date, your name and address, the goods or services delivered, and the VAT amount. Note: a simplified invoice is not allowed for intra-EU supplies, distance sales or supplies in another EU country where VAT is shifted to the buyer.

3. VAT rates and reverse charge

The Netherlands has three VAT rates plus exemptions. Picking the right one is your responsibility — getting it wrong means correcting the invoice and the VAT return.

When VAT is shifted: "btw verlegd"

Under the reverse charge scheme (verleggingsregeling) you do not calculate VAT yourself — your business customer reports and pays it. This is common in construction subcontracting and intra-EU B2B services. Your invoice must show: "btw verlegd", the btw-id of your customer, and the amount per VAT rate. You still report the turnover (without VAT) in the right section of your VAT return.

4. Payment terms and statutory interest

You're free to agree on a payment term — but the law caps how long a customer may make you wait. The rules differ by customer type.

Statutory interest in 2026

• Wettelijke handelsrente (B2B): 10.15% per 1 January 2026 (unchanged since 1 July 2025). Runs automatically from the day after the due date — no reminder needed.
• Wettelijke rente (consumer/non-commercial): 4% per 1 January 2026 (down from 6% in 2025). Requires a notice of default (ingebrekestelling) first.

For the complete process of chasing late payments, statutory collection costs (€40 minimum for B2B), and when to engage a collection agency, see our deep dive on invoices and payments.

5. Invoice numbers, deadline and retention

Numbering rules

Two rules from the Belastingdienst, no exceptions:

• Each invoice number is unique — no duplicates anywhere in your administration.
• Numbers must be sequential within a logical series. Gaps raise red flags during audits because they suggest missing invoices.

When to send: the 15th-of-next-month rule

You must send your invoice no later than the 15th day of the month following the month in which you delivered. Send it later and you still owe the VAT in the original period — the Belastingdienst does not let you push revenue into a later quarter by stalling on paperwork.

Retention period (bewaarplicht)

Keep both your sales invoices and the invoices you receive for 7 years. For invoices relating to real estate (purchase, lease, refurbishment of business premises) the retention period is 10 years. You may store invoices in the form you sent or received them — a digitally received invoice stays digital, you do not need to print it.

6. E-invoicing: Peppol, UBL and the 2030 deadline

A PDF attached to an email is not an e-invoice. A real e-invoice is a structured machine-readable file that your customer's accounting software can process automatically — no retyping, no errors.

UBL vs. Peppol — what's the difference?

• UBL (Universal Business Language) is the underlying XML syntax — a structured file with tagged data (sender, recipient, line items, VAT, totals).
• Peppol is the secure international network that delivers e-invoices between businesses. Think of UBL as the language and Peppol as the postal service.
• In Dutch Peppol traffic two message formats are registered and mandatory: SI-UBL 2.0 (NLCIUS), used mainly for domestic invoices, and Peppol BIS Billing 3.0, more often used internationally. Both can be used domestically and both align with the EU norm EN 16931.

Is it mandatory in 2026?

7. The 8 most common invoice mistakes

1. Using the ob-nummer instead of the btw-id. Privacy leak — your BSN ends up on every invoice. Always use the NL...B01 number.
2. Non-sequential invoice numbers. Gaps in the series are an immediate red flag in a Belastingdienst audit. Use software that auto-increments.
3. Vague descriptions ("consulting", "services rendered"). Be specific: what was delivered, for which project or period, and at what rate. This also prevents discussions about scope.
4. Missing the delivery date. Required separately from the invoice date when they differ. Without it the Belastingdienst cannot determine the correct VAT period.
5. Wrong VAT rate. Especially after the 2026 logies change. When in doubt, check the Belastingdienst's rate table for your specific service.
6. Forgetting to mention "btw verlegd" + customer VAT number. Without this text, your customer cannot self-account for the VAT and the Belastingdienst will demand it from you.
7. Sending invoices after the 15th of the following month. The VAT is still due in the original period — you only create a cash-flow problem.
8. Stating a payment "term" instead of a concrete due date. "Within 30 days" is ambiguous; "Pay before 10 June 2026" is not. The latter speeds up payment and removes excuses.

8. Quick checklist before sending

Related reading

• Invoices and payments: payment terms, statutory interest and collection
• VAT return for dummies: step by step
• VAT deadlines 2026
• Small business scheme (KOR) 2026