What is EN 16931?
Last reviewed 2026-06-07. Mandate dates change - verify against the official national portal before acting.
EN 16931:2017 is the European standard that defines the semantic model of an electronic invoice - the set of business terms (BT) and groups (BG) every compliant invoice must express. It is syntax-neutral: the same semantics are carried by two XML syntaxes, UBL 2.1 and UN/CEFACT CII.
Semantics vs syntax
EN 16931 specifies WHAT an invoice means (BT-1 invoice number, BG-22 totals, and so on), not how the XML is shaped. UBL and CII are the two permitted syntaxes that carry those semantics.
CIUS and national profiles
Countries add Core Invoice Usage Specifications (CIUS) on top - XRechnung (Germany), PEPPOL BIS (pan-EU), OIOUBL (Denmark), Factur-X (France/Germany). All remain EN 16931-compliant.
Why a canonical model matters
Because every compliant format shares the EN 16931 semantics, you can convert between them through that common model. Facturus parses each format into EN 16931 and serialises back out - which is why some conversions are lossless and others (like FatturaPA) are lossy.