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Creating your first invoice: what must be on it?
Written by Ilias3 min read
Your first assignment is in and now you need to send an invoice. An invoice is more than an amount and a bank account number: the tax authorities have requirements for what it must contain. An incomplete invoice can cause problems with your VAT. This article explains exactly which details are mandatory.
Which details are mandatory on an invoice?
Every invoice must show your business name and address, your VAT identification number and your KvK number. You also state the name and address of your client, a unique invoice number, the invoice date and the date of delivery. In addition you put a description of what you delivered, the amount excluding VAT, the VAT rate and amount, and the total amount.
Why is a unique invoice number important?
Invoice numbers must be sequential and unique. So you may not skip numbers or use them twice. The tax authorities use this to check whether your records are complete. A logical structure, for example by year and sequence number, keeps it clear.
When do you not charge VAT?
In some cases you don't charge VAT, for example under the reverse-charge scheme or with clients abroad. Then you put no VAT on the invoice, but state why: for example 'VAT reverse-charged' with your client's VAT number. If you fall under the KOR small business scheme, you also invoice without VAT.
How do you keep your invoices?
You're obliged to keep your invoices for seven years, both the invoices you send and those you receive. A digital copy is allowed. Preferably use bookkeeping software that numbers and stores your invoices automatically; that prevents mistakes and saves time at your VAT return.
This article provides general information based on the rules known for 2026 and does not replace personal tax advice. For your specific situation, we're happy to take a look with you.
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