What must an invoice contain? The 10 legal requirements

The 10 requirements for a full invoice

A payment deadline and bank details are not legal requirements, but they belong on the invoice in practice — without them, the customer doesn't know when or where to pay.

• Invoice date (the date of issue)
• A sequential invoice number
• Your CVR number (VAT registration number)
• Your name and address
• The buyer's name and address
• The quantity and nature of the goods or services supplied
• The delivery date, if it differs from the invoice date
• The unit price excluding VAT, and any discounts
• The VAT base and the applicable VAT rate (typically 25%)
• The VAT amount itself in kroner

Simplified invoices for small sales

For sales under 3,000 kr. a simplified invoice — such as a till receipt — is enough. It must still show the date and number, your name and CVR number, what was supplied, and the VAT amount. If a business customer asks for a full invoice, though, you must issue one.

Invoices without VAT

If you sell VAT-exempt services, or to businesses in other EU countries under the reverse-charge rules, the invoice must explain why no VAT is added — for example with the wording "reverse charge" and the buyer's VAT number. Without the explanation, the invoice isn't valid and your customer can run into trouble with their own deduction.

Mistakes are fixed with a credit note

If you've sent a wrong invoice, you must not simply delete or overwrite it — the number sequence has to stay unbroken. Instead, issue a credit note that cancels the wrong invoice, and create a new one with the correct content. The credit note must reference the original invoice.

Selling to the public sector: e-invoicing

Public-sector customers can't accept PDF or paper invoices. They must receive an electronic invoice sent via NemHandel to the institution's EAN number — an accounting system with e-invoicing handles that for you.

Storage and bookkeeping

Invoices are accounting records and must be kept for at least 5 years after the end of the financial year — both the ones you send and the ones you receive. Under the Danish Bookkeeping Act this must happen digitally in a bookkeeping system, so drop the binder and let the system store them automatically.

Invoicing with the bookkeeping included

In Numina's accounting software your invoices meet the requirements automatically: sequential numbering, correct VAT and e-invoices for public-sector customers. And because the bookkeeper is part of the price, every invoice is also booked, reconciled against the payment and included in your VAT return — without you lifting a finger.