# BT-91 Debited account identifier

Identifier of the account that will be debited in a direct debit payment.

## Quick answer

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

- [Validate XML](/en/xrechnung-validator?source=resource&bt=BT-91)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&bt=BT-91)

## In plain language

Use this only in direct debit scenarios where the payer account must be part of the structured invoice.

## What you usually enter here

Debtor account identifier, usually IBAN

Typical valid values include: DE44500105175407324931

Required by BR-DE-31 when direct debit group BG-19 is present. BR-DE-20 recommends a valid IBAN for SEPA code 59.

## Where the field sits

BT-91 belongs to the Payment part of the invoice. UBL 2.1 Syntax: Invoice › cac:PaymentMeans › cac:PayerFinancialAccount › cbc:ID. CII (UN/CEFACT) Syntax: rsm:CrossIndustryInvoice › rsm:SupplyChainTradeTransaction › ram:ApplicableHeaderTradeSettlement › ram:SpecifiedTradeSettlementPaymentMeans › ram:PayerPartyDebtorFinancialAccount › ram:IBANID.

## What goes wrong often

Avoid values like: 12345

Relevant rule codes: BR-DE-31

## Valid Examples

- DE44500105175407324931

## Invalid Examples

- 12345

## Related Fields

- [BT-89 Mandate reference identifier](/resources/xrechnung/bt-89-mandate-reference-identifier)
- [BT-90 Bank assigned creditor identifier](/resources/xrechnung/bt-90-bank-assigned-creditor-identifier)

## 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-91

### Data Type:
identifier

### Cardinality:
0..1

### Requirement:
Optional

### Max Length:
35 characters

## XML Implementation

### UBL 2.1 Syntax
```
/Invoice/cac:PaymentMeans/cac:PayerFinancialAccount/cbc:ID
```

### CII (UN/CEFACT) Syntax
```
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeSettlement/ram:SpecifiedTradeSettlementPaymentMeans/ram:PayerPartyDebtorFinancialAccount/ram:IBANID
```

## Validation Rules

### BR-DE-31
Debited account identifier (BT-91) is required when direct debit is used

## Check whether your XRechnung sets BT-91 correctly

Upload the XML file to the free validator. It applies the KoSIT rules for XRechnung 3.0 and names each finding with its rule ID, for this field for example BR-DE-31. Creating a new invoice instead? The converter checks the invoice against the same rules and shows the findings before download.

- [Validate XML](/en/xrechnung-validator)
- [Convert invoice](/en/pdf-to-xrechnung)

Free, no account needed. XML file up to 2 MB.

## Official sources and tools

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