Reference
Markdown exportBT-1 Invoice Number
A unique identification of the Invoice. The identification scheme shall provide uniqueness within the business relationship between the Seller and the Buyer.
BT-1 (Invoice number) is the identifier the seller assigns once to the invoice. It is mandatory under EN 16931 and German UStG §14. The seller may use one or more identifiable number sequences; the sequence does not have to be gapless. Example: 2024-INV-0042.
BT-1 · EN 16931 / XRechnung 3.x
BT Reference Card
Key EN 16931 and XRechnung facts for this business term.
- BT code
BT-1- Name
- Invoice Number
- Cardinality
- Mandatory (M)
- Business group
- Document
- Data type
- Identifier
- Example value
2024-INV-0042- Common error
- BR-02: An Invoice shall have an Invoice number. Under German UStG §14(4)(4), the issuer assigns it once from one or more number sequences. A gapless sequence is not required.
Quick answer
A unique identification of the Invoice. The identification scheme shall provide uniqueness within the business relationship between the Seller and the Buyer.
Invoice basics
Core document identifiers, dates, process identifiers, and high-level invoice context.
Quick actions
In plain language
A unique identification of the Invoice. The identification scheme shall provide uniqueness within the business relationship between the Seller and the Buyer.
A unique identification of the Invoice. The identification scheme shall provide uniqueness within the business relationship between the Seller and the Buyer.
The invoice number identifies the invoice in accounting, payment, and audit records. The issuer must assign it once within its numbering system.
What you usually enter here
Alphanumeric string without spaces or special characters except hyphens
Typical valid values include: INV-2024-001, RE20240327001, R-2024-03-15-001, 2024-INV-12345
Mandatory under EN 16931-1. Section 14(4)(4) UStG requires a number from one or more sequences that the issuer assigns once. UStAE 14.5 states that the sequence does not need to be gapless.
What goes wrong often
Avoid values like: , , INV 001, INV/001/2024
Relevant rule codes: BR-02
Examples in context
The invoice number identifies the invoice in accounting, payment, and audit records. The issuer must assign it once within its numbering system.
Mandatory under EN 16931-1. Section 14(4)(4) UStG requires a number from one or more sequences that the issuer assigns once. UStAE 14.5 states that the sequence does not need to be gapless.
Valid Examples
- INV-2024-001
- RE20240327001
- R-2024-03-15-001
- 2024-INV-12345
- F-20240327-001
Invalid Examples
- INV 001
- INV/001/2024
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-1
Data Type:
text
Cardinality:
1..1
Requirement:
Mandatory
Max Length:
35 characters
Since Version:
XRechnung 1.0+
XML Implementation
/Invoice/cbc:ID/CrossIndustryInvoice/ExchangedDocument/ram:IDValidation Rules
BR-02
BR-02
Why the standard cares about this field
Business Context
The invoice number identifies the invoice in accounting, payment, and audit records. The issuer must assign it once within its numbering system.
Legal Requirement
Mandatory under EN 16931-1. Section 14(4)(4) UStG requires a number from one or more sequences that the issuer assigns once. UStAE 14.5 states that the sequence does not need to be gapless.
FAQ
Can I use the same invoice number for different customers?
No. The issuer must assign each invoice number once. You can use separate identifiable number ranges, but a different customer does not make reuse of the same number valid.
What are the requirements for invoice numbering in Germany?
Use one or more identifiable number ranges and assign each invoice number once. German guidance does not require a gapless sequence, but the records must still identify each invoice clearly.