Denmark e-Invoicing Guide

Denmark was one of the first countries to mandate electronic invoices for government suppliers. From 1 February 2005 Danish public institutions could only receive invoices in electronic form, and the NemHandel infrastructure and OIOUBL format have been central to Danish digital administration ever since.

B2B e-invoicing remains voluntary. What Denmark has instead is the 2022 Bookkeeping Act, which requires most businesses to record transactions in a digital bookkeeping system and requires those systems to support automatic sending and receiving of e-invoices. The formats are set by executive order, which names OIOUBL over Nemhandel and Peppol BIS. In March 2026 Erhvervsstyrelsen consulted on replacing OIOUBL with a single national format built on Peppol BIS 4 and Danish extensions under the PINT architecture. The consultation note published on 27 May 2026 confirmed the move and refers to the format as Nemhandel Faktura, because the agency does not want to use naming controlled by private parties. Full transition is targeted for mid-2029.

Denmark's e-invoicing timeline reflects its long history with electronic invoicing. B2G has been mandatory since February 2005, and the duty on public bodies to receive invoices meeting the European standard took effect on 18 April 2019 for state contracting authorities and central purchasing bodies, and on 18 April 2020 for other non-state contracting authorities. The planned OIOUBL 3.0 update was cancelled on 14 January 2026, and in March 2026 Erhvervsstyrelsen consulted on replacing OIOUBL with a single Peppol BIS 4 based format. The draft migration path runs from a release candidate in November 2027, through a final release in May 2028 and mandatory support in November 2028, to the end of OIOUBL 2.1 in May 2029; the split of the 18-month migration window between test, phase-in and phase-out is still being agreed with stakeholders. Digital bookkeeping reached its last group, businesses without an annual report duty and turnover above DKK 300,000, on 1 January 2026, and registered bookkeeping systems must support SAF-T 2.0 from 1 January 2027.

Suppliers to the public sector must send invoices so that they are received electronically, and a public authority may postpone payment of an invoice that does not meet the content and transmission requirements. B2B e-invoicing is voluntary: businesses may adopt Peppol or OIOUBL with their trading partners, but there is no legal obligation to do so. Under the published strategy OIOUBL is replaced by a single Peppol BIS 4 based format by May 2029. The initial scope covers invoices, credit notes and invoice responses; other document types such as e-orders and e-receipts stay in both OIOUBL and Peppol formats for the time being.

The Bookkeeping Act applies to businesses that file an annual report and to those whose net turnover exceeded DKK 300,000 in two consecutive income years. Its reach is not limited to Danish-registered companies: section 1 catches business activities carried out in Denmark by businesses domiciled abroad, and branches abroad of a Danish business count as part of that business. Those businesses must record transactions in a digital bookkeeping system, and registered systems must support SAF-T 2.0 from 1 January 2027. The Act does not mandate e-invoicing itself, but it requires the systems to be capable of it. A separate consultation that closed on 17 August 2026 would go further, obliging providers of registered systems to enrol their business customers for e-invoice receipt in the Nemhandel register unless the customer declines within four weeks of being notified, to present e-invoice as the first option where the recipient is registered, and to confirm identities with MitID. The notification duty is set to commence on 30 November 2026 and the rest of the order on 1 January 2027. B2C transactions sit outside any e-invoicing framework, and businesses below the turnover threshold with no annual report duty are outside the digital bookkeeping requirement.

Denmark uses a decentralised exchange model. Businesses connect to NemHandel or the Peppol network through access points, using CVR numbers for routing. There is no central government clearance or pre-authorisation. Invoices are exchanged directly between parties through the network.

For B2G, invoices are sent over Nemhandel in OIOUBL or over Peppol using the Danish CIUS of Peppol BIS Billing 3.0. Under the published strategy Denmark moves to a single format based on Peppol BIS 4 with the PINT (Peppol INTernational) architecture, which allows Danish national extensions to sit on top of the international Peppol core without breaking cross-border interoperability. Once the transition completes, the bookkeeping rules will require only the Peppol-based format rather than OIOUBL as well.

Penalties in Denmark apply to the public sector invoicing rules and to the Bookkeeping Act. A public authority may postpone payment of an invoice that does not meet the requirements and must tell the supplier as soon as possible. Fines under the Bookkeeping Act run up to DKK 1.5 million, scaled by turnover, the gravity and duration of the breach and whether it is repeated. Erhvervsstyrelsen runs risk-based checks: a business booking outside a digital system first gets an order with a deadline, and repeated or substantial breaches are reported to the police.