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EN 16931 Field Mapper for Peppol UBL and CII

Look up any EN 16931 business term and see its UBL 2.1 and CII XML path side by side. Free reference for Peppol BIS 3.0, XRechnung, and Factur-X. No signup.

Coverage
115 EN 16931 business terms
Syntaxes
UBL 2.1 and CII paths side by side
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Look up an EN 16931 business term

UBL 2.1, CII

Search by BT ID, name, description or XML path.

115 of 115 business terms

Invoice - Invoice (top level)

BG-1 - Invoice note

BG-2 - Process control

BG-4 - Seller

BG-5 - Seller postal address

BG-6 - Seller contact

BG-7 - Buyer

BG-8 - Buyer postal address

BG-10 - Payee

BG-13 - Delivery information

BG-15 - Deliver to address

BG-16 - Payment instructions

BG-17 - Credit transfer

BG-20 - Document level allowances

BG-22 - Document totals

BG-23 - VAT breakdown

BG-25 - Invoice line

BG-29 - Price details

BG-30 - Line VAT information

BG-31 - Item information

Definition. What is EN 16931?

EN 16931 is the European standard for the semantic data model of an electronic invoice. It was developed by CEN (European Committee for Standardization) and adopted by the EU to ensure interoperability across all member states. The standard defines business terms (BT) and business groups (BG) that describe the meaning of each invoice field, independent of any specific XML format.

EN 16931 is required by EU Directive 2014/55/EU for public procurement invoicing. It forms the foundation of the Belgian e-invoicing mandate (January 2026) and the upcoming EU ViDA regulation for cross-border B2B e-invoicing.

One business term as the mapper shows it: BT-112, the invoice total with VAT, with its UBL 2.1 path and its CII path.

Two syntaxes. UBL vs CII: Two Syntaxes, One Standard.

  • UBL 2.1 (OASIS)

    Universal Business Language. Uses cbc/cac namespace prefixes. The syntax chosen by Peppol BIS 3.0 and used across most of Europe for Peppol invoicing. Paths start with /Invoice/.

  • CII (UN/CEFACT)

    Cross Industry Invoice. Uses rsm/ram namespace prefixes. The syntax used by ZUGFeRD (Germany), Factur-X (France), and XRechnung (supports both). Paths start with /rsm:CrossIndustryInvoice/.

Both syntaxes express the same EN 16931 semantic model. Every business term maps to exactly one XML element in each syntax. This tool shows you both paths side by side, so you can easily translate between UBL and CII or build support for both formats.

Three steps. How to use this reference.

  1. Search for a business term

    Type any BT ID (e.g. "BT-1"), field name (e.g. "invoice number"), or even an XML element name (e.g. "PayableAmount") to find the matching term.

  2. Filter by group or data type

    Use the filters to narrow down to a specific business group (e.g. BG-4 Seller) or data type (e.g. Amount, Code). Toggle between UBL-only, CII-only, or both paths.

  3. Expand and copy paths

    Click any row to expand it and see the full description, data type, and cardinality. Use the copy button to copy the exact XML path for your code.

In practice. EN 16931 in Practice.

The EN 16931 semantic model is the foundation of every major e-invoicing standard in Europe. Here is how different standards use it:

  • Peppol BIS Billing 3.0

    Uses UBL 2.1 syntax. The standard for cross-border B2B e-invoicing via the Peppol network. Mandatory in Belgium since January 2026 for B2B invoices.

  • XRechnung (Germany)

    Supports both UBL 2.1 and CII syntaxes. Required for invoicing to German public authorities. Adds national rules (CIUS) on top of EN 16931.

  • ZUGFeRD / Factur-X

    Uses CII syntax embedded in PDF/A-3 files. A hybrid format that combines a human-readable PDF with machine-readable XML. Popular in Germany, France, and growing across Europe.

  • NLCIUS (Netherlands)

    Uses UBL 2.1 syntax. The Dutch CIUS (Core Invoice Usage Specification) adds country-specific rules for invoicing in the Netherlands.

Runs in your browser

This tool is a static reference that runs entirely in your browser. Your searches and filters are not sent to any server. No account required. Bookmark it and use it anytime.

FAQ. Frequently asked questions.

Something else? Write to hello@e-invoice.be.

What is the difference between EN 16931 and UBL?

EN 16931 defines the semantic data model: what information an e-invoice must contain (business terms like Invoice number, Seller name, etc.). UBL 2.1 is one of two XML syntaxes used to express that model in a machine-readable format. CII is the other. Think of EN 16931 as the 'what' and UBL/CII as the 'how'.

Does Peppol use UBL or CII?

Peppol BIS Billing 3.0 uses UBL 2.1 syntax exclusively. If you are building a Peppol integration, you only need the UBL column in this reference. CII is used by ZUGFeRD, Factur-X, and optionally by XRechnung.

What does cardinality mean?

Cardinality defines how many times a business term can or must appear. '1..1' means mandatory (exactly once). '0..1' means optional (zero or one time). '0..n' means optional and repeatable (zero or more times). Some terms that are optional in EN 16931 may be mandatory in specific CIUS implementations like Peppol BIS.

Is this a complete list of all EN 16931 fields?

This reference covers the most commonly used business terms and groups from EN 16931. It includes all header-level fields, seller and buyer information, payment instructions, document totals, VAT breakdown, invoice lines, price details, and item information.

Can I use this to convert between UBL and CII?

This reference shows the XML path mappings, which is the first step in building a UBL-to-CII or CII-to-UBL converter. However, format conversion also requires handling differences in date formats, namespace declarations, element ordering, and attribute handling.

How does EN 16931 relate to the Belgian e-invoicing mandate?

Since January 2026, all B2B invoices in Belgium must be sent electronically via the Peppol network. Peppol uses UBL 2.1 following the EN 16931 semantic model. This means every Belgian B2B invoice must contain the mandatory EN 16931 business terms mapped to UBL 2.1 XML elements.

What is a CIUS (Core Invoice Usage Specification)?

A CIUS is a country-specific or domain-specific restriction of EN 16931. It can make optional fields mandatory or restrict allowed values, but cannot add new fields or relax existing rules. Examples include Peppol BIS Billing 3.0, XRechnung (Germany), NLCIUS (Netherlands), and the Belgian UBL CIUS.

What are the mandatory fields in EN 16931?

Fields with cardinality 1..1 are mandatory. Key mandatory fields include: Invoice number (BT-1), Issue date (BT-2), Invoice type code (BT-3), Currency code (BT-5), Seller name (BT-27), Buyer name (BT-44), Line identifier (BT-126), Invoiced quantity (BT-129), Net amount (BT-131), Item name (BT-153), and all document totals (BT-106 through BT-115).

How does EN 16931 relate to the German e-invoicing mandate?

Germany requires all businesses to receive e-invoices since January 2025, with mandatory sending phased in from 2027-2028. XRechnung is the German CIUS of EN 16931 and can be expressed in either UBL or CII syntax. ZUGFeRD 2.x invoices at the EN 16931 profile level also comply.

What is the difference between a Business Group (BG) and a Business Term (BT)?

Business Groups (BG) are logical containers that organize related Business Terms (BT). For example, BG-4 (Seller) groups all seller-related terms like Seller name (BT-27), Seller VAT identifier (BT-31), and Seller address fields. BGs help structure the invoice data model but do not appear directly in the XML.

Next step. More free Peppol tools and guides.

Tools

Guides

Build with the Peppol API.

Send and receive EN 16931-compliant invoices via our REST API. No XML assembly required.

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