# BT-9 Payment Due Date

The date when the payment is due. This date is calculated based on payment terms and invoice date, providing clear payment deadlines for cash flow management.

> BT-9 (Payment due date) is the calendar date by which the buyer must settle the amount due. Optional under EN 16931 but expected by most German B2G receivers. Provide in ISO 8601 (YYYY-MM-DD); may be omitted when BT-20 (Payment terms) carries the information instead. Example: 2024-04-26.
>
> BT-9 · EN 16931 / XRechnung 3.x

## BT Reference Card

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

- **BT code**: BT-9
- **Name**: Payment Due Date
- **Cardinality**: Optional (O)
- **Business group**: Document
- **Data type**: Date
- **Example value**: 2024-04-26

## Quick answer

The date when the payment is due. This date is calculated based on payment terms and invoice date, providing clear payment deadlines for cash flow management.

> **Delivery and payment**: Delivery dates, payment means, and the operational context around settlement.

## In plain language

The date when the payment is due. This date is calculated based on payment terms and invoice date, providing clear payment deadlines for cash flow management.

The date when the payment is due. This date is calculated based on payment terms and invoice date, providing clear payment deadlines for cash flow management.

Essential for payment processing, cash flow management, and establishing clear payment deadlines. Helps buyers plan their payment schedules and suppliers manage receivables.

## What you usually enter here

YYYY-MM-DD (ISO 8601 date format)

Typical valid values include: 2025-01-15, 2025-02-28, 2025-12-31, 2026-06-15

Optional but highly recommended for commercial transactions to establish clear payment expectations and support dispute resolution

## What goes wrong often

Avoid values like: 15.01.2025, 2025/01/15, 01-15-2025, 2025-13-01

Relevant rule codes: BR-CO-19

## Examples in context

Essential for payment processing, cash flow management, and establishing clear payment deadlines. Helps buyers plan their payment schedules and suppliers manage receivables.

Optional but highly recommended for commercial transactions to establish clear payment expectations and support dispute resolution

## Valid Examples

- 2025-01-15
- 2025-02-28
- 2025-12-31
- 2026-06-15

## Invalid Examples

- 15.01.2025
- 2025/01/15
- 01-15-2025
- 2025-13-01
- 2024-02-30

## Related Fields

Essential for payment processing, cash flow management, and establishing clear payment deadlines. Helps buyers plan their payment schedules and suppliers manage receivables.

- [BT-2 Invoice Issue Date](/resources/xrechnung/bt-2-invoice-issue-date)
- [BT-20 Payment Terms](/resources/xrechnung/bt-20-payment-terms)
- [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-9

### Data Type:
date

### Cardinality:
0..1

### Requirement:
Optional

### Since Version:
Optional

## XML Implementation

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

### CII (UN/CEFACT) Syntax
```
/CrossIndustryInvoice/SupplyChainTradeTransaction/ApplicableHeaderTradeSettlement/ram:SpecifiedTradePaymentTerms/ram:DueDateDateTime
```

## Validation Rules

### BR-CO-19
BR-CO-19

## Why the standard cares about this field

### Business Context
Essential for payment processing, cash flow management, and establishing clear payment deadlines. Helps buyers plan their payment schedules and suppliers manage receivables.

### Legal Requirement
Optional but highly recommended for commercial transactions to establish clear payment expectations and support dispute resolution

## FAQ

### How is the payment due date calculated?
The payment due date is typically calculated by adding the payment terms period (e.g., 30 days) to the invoice date. It can also be explicitly specified in the invoice.

### Is the payment due date mandatory in XRechnung?
No, the payment due date (BT-9) is optional in XRechnung. However, it's highly recommended for clear payment management and is often expected in business transactions.

### What happens if no payment due date is specified?
If no payment due date is specified, the buyer typically follows standard payment terms or legal defaults (usually 30 days from invoice date in German commercial law).

### Can the payment due date be earlier than the invoice date?
Generally no. The payment due date should be the same as or later than the invoice date. Earlier dates would indicate prepayment scenarios which require special handling.

## 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)