Reference
Markdown exportBT-31 Seller VAT Identifier
The seller's VAT identifier (also known as VAT registration number). For German companies, this follows the format DE + 9 digits.
BT-31 (Seller VAT identifier) is the supplier's VAT registration number, prefixed by the ISO 3166-1 country code. Conditional in EN 16931: required whenever the invoice has any VAT amount (BR-CO-9), unless BT-32 (tax registration identifier) is supplied instead. Example: DE123456789.
BT-31 · EN 16931 / XRechnung 3.x
BT Reference Card
Canonical EN 16931 / XRechnung facts for this business term — citable from this anchor.
- BT code
BT-31- Name
- Seller VAT Identifier
- Cardinality
- Conditional (C)
- Business group
- BG-4 SELLER
- Data type
- Identifier
- Example value
DE123456789- Common error
- BR-CO-9: At least one of BT-31 (Seller VAT identifier) or BT-32 (Seller tax registration identifier) must be present whenever the invoice contains VAT (BG-23).
Quick answer
The seller's VAT identifier (also known as VAT registration number). For German companies, this follows the format DE + 9 digits.
Seller details
Who issued the invoice and how the recipient can identify that business reliably.
In plain language
The seller's VAT identifier (also known as VAT registration number). For German companies, this follows the format DE + 9 digits.
The seller's VAT identifier (also known as VAT registration number). For German companies, this follows the format DE + 9 digits.
Critical for VAT compliance and cross-border trade within the EU. Required when the seller is subject to VAT.
What you usually enter here
Country code (2 letters) + national VAT number
Typical valid values include: DE123456789, AT12345678, FR12345678901, NL123456789B01
Required if the seller is registered for VAT according to EU VAT Directive 2006/112/EC
What goes wrong often
Avoid values like: 123456789, DE12345678, DE1234567890, DE 123456789
Relevant rule codes: BR-CO-26, BR-DE-16
Examples in context
Critical for VAT compliance and cross-border trade within the EU. Required when the seller is subject to VAT.
Required if the seller is registered for VAT according to EU VAT Directive 2006/112/EC
Valid Examples
Use these points as the practical checks for this section.
- DE123456789
- AT12345678
- FR12345678901
- NL123456789B01
- IT12345678901
Invalid Examples
Use these points as the practical checks for this section.
- 123456789
- DE12345678
- DE1234567890
- DE 123456789
- de123456789
XML mapping and field facts
Open the technical reference if you need XML paths, validator rule codes, legal wording, or schema-specific mapping details.
Field ID:
BT-31
Data Type:
identifier
Cardinality:
0..1
Requirement:
Optional
Max Length:
30 characters
Since Version:
Conditional (required if subject to VAT)
XML Implementation
/Invoice/cac:AccountingSupplierParty/cac:Party/cac:PartyTaxScheme/cbc:CompanyID/CrossIndustryInvoice/SupplyChainTradeTransaction/ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:SpecifiedTaxRegistration/ram:ID[@schemeID="VA"]Validation Rules
BR-CO-26
BR-CO-26
BR-DE-16
BR-DE-16
Why the standard cares about this field
Business Context
Critical for VAT compliance and cross-border trade within the EU. Required when the seller is subject to VAT.
Legal Requirement
Required if the seller is registered for VAT according to EU VAT Directive 2006/112/EC
FAQ
What is the format for German VAT identifiers?
German VAT identifiers follow the format "DE" followed by exactly 9 digits (e.g., DE123456789). No spaces or special characters are allowed.
Is the VAT identifier mandatory for all sellers?
No, it is only required if the seller is registered for VAT. Small businesses below the VAT threshold or VAT-exempt entities may not have a VAT identifier.
How can I validate a VAT identifier?
Use the EU VIES system (ec.europa.eu/taxation_customs/vies/) to validate VAT identifiers. Each country has specific format requirements.
What about other EU countries VAT formats?
Each EU country has its own VAT number format: AT (8 digits), FR (11 characters), NL (12 characters), IT (11 digits), etc. Always include the country code prefix.