# BT-2 Invoice Issue Date

The date when the Invoice was issued.

> BT-2 (Invoice issue date) is the calendar date on which the seller issued the invoice. Mandatory under EN 16931, it must be supplied in ISO 8601 (YYYY-MM-DD) form. The issue date drives VAT reporting periods, payment-term countdowns, and audit trails. Example: 2024-03-27.
>
> BT-2 · EN 16931 / XRechnung 3.x

## BT Reference Card

Canonical EN 16931 / XRechnung facts for this business term — citable from this anchor.

- **BT code**: BT-2
- **Name**: Invoice Issue Date
- **Cardinality**: Mandatory (M)
- **Business group**: Document
- **Data type**: Date
- **Example value**: 2024-03-27
- **Common error**: BR-3: An Invoice shall have an Invoice issue date. Must be ISO 8601 (YYYY-MM-DD); locale formats like 27.03.2024 are rejected by KoSIT.

## Quick answer

The date when the Invoice was issued.

> **Invoice basics**: Core document identifiers, dates, process identifiers, and high-level invoice context.

## In plain language

The date when the Invoice was issued.

The date when the Invoice was issued.

The invoice issue date determines when the invoice becomes legally effective and starts payment terms. It is important for VAT reporting periods and legal compliance.

## What you usually enter here

ISO 8601 date format (YYYY-MM-DD)

Typical valid values include: 2024-03-27, 2024-12-31, 2025-01-01

Mandatory according to EN 16931-1 and German VAT law (UStG §14). The date must be accurate for VAT reporting and legal enforceability.

## What goes wrong often

Avoid values like: 27.03.2024, 03/27/2024, 2024-13-01, 2024-02-30

Relevant rule codes: BR-2

## Examples in context

The invoice issue date determines when the invoice becomes legally effective and starts payment terms. It is important for VAT reporting periods and legal compliance.

Mandatory according to EN 16931-1 and German VAT law (UStG §14). The date must be accurate for VAT reporting and legal enforceability.

## Valid Examples

- 2024-03-27
- 2024-12-31
- 2025-01-01

## Invalid Examples

- 27.03.2024
- 03/27/2024
- 2024-13-01
- 2024-02-30

## Related Fields

The invoice issue date determines when the invoice becomes legally effective and starts payment terms. It is important for VAT reporting periods and legal compliance.

- [BT-1 Invoice Number](/resources/xrechnung/bt-1-invoice-number)
- [BT-3 Invoice Type Code](/resources/xrechnung/bt-3-invoice-type-code)
- [BT-7 Value Added Tax Point Date](/resources/xrechnung/bt-7-vat-point-date)
- [BT-8 VAT point date code](/resources/xrechnung/bt-8-vat-point-date-code)
- [BT-9 Payment Due Date](/resources/xrechnung/bt-9-payment-due-date)

## 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-2

### Data Type:
date

### Cardinality:
1..1

### Requirement:
Mandatory

### Since Version:
XRechnung 1.0+

## XML Implementation

### UBL 2.1 Syntax
```
/Invoice/cbc:IssueDate
```

### CII (UN/CEFACT) Syntax
```
/CrossIndustryInvoice/ExchangedDocument/ram:IssueDateTime/udt:DateTimeString
```

## Validation Rules

### BR-2
BR-2

## Why the standard cares about this field

### Business Context
The invoice issue date determines when the invoice becomes legally effective and starts payment terms. It is important for VAT reporting periods and legal compliance.

### Legal Requirement
Mandatory according to EN 16931-1 and German VAT law (UStG §14). The date must be accurate for VAT reporting and legal enforceability.

## FAQ

### Can the invoice issue date be in the future?
Generally no. The invoice issue date should be the actual date when the invoice was created and sent to the customer.

### How does the invoice issue date affect VAT reporting?
The invoice issue date determines in which VAT reporting period the invoice must be included for both the issuer and recipient.

## Official sources and tools

- [KoSIT Validator](https://erechnungsvalidator.service-bw.de/)
- [Invoice Converter](/pdf-to-xrechnung)
- [XRechnung Standard](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)