Public sector only
Mandatory for B2G since 2005; no B2B mandate, but every business must be ABLE to invoice electronically.
| 2005 | B2G e-invoicing mandatory, via NemHandel |
| 1 Jan 2026 | Bookkeeping Act: digital bookkeeping and e-invoicing CAPABILITY required |
| 1 Jul 2026 | same, for businesses running their own in-house systems |
| Nov 2028 | NemHandel BIS 4 (Peppol BIS 4 / PINT) becomes mandatory |
| May 2029 | OIOUBL 2.1 phased out |
Format: OIOUBL 2.1 today; NemHandel BIS 4 (Peppol BIS 4 with PINT) from 2028
Transmission: NemHandel or Peppol
The distinction that trips people up: the 2022 Bookkeeping Act does NOT make B2B e-invoicing compulsory. It requires businesses to keep digital records in a system that CAN send and receive e-invoices — the capability, not the act. There is still no obligation to issue a B2B invoice electronically if your customer does not want one. B2G has been genuinely mandatory since 2005 and runs over NemHandel, which is being migrated onto Peppol: OIOUBL 2.1 gives way to NemHandel BIS 4 (Peppol BIS 4 with PINT) from November 2028, with OIOUBL retired by May 2029. If you are building for Denmark now, target Peppol BIS and treat OIOUBL as legacy.
Validate a Denmark invoice against the profile that applies here — Peppol BIS Billing 3.0 (+ national rules).
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The Peppol profile also applies this country's own rules, and they are switched on automatically from the seller's country — no extra parameter. See the 14 Denmark rules this validator checks →