# BT-14 Sales order reference

Reference to the seller-side sales order behind the invoice.

## Quick answer

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

- [Validate XML](/en/xrechnung-validator?source=resource&bt=BT-14)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&bt=BT-14)

## In plain language

Reference to the seller-side sales order behind the invoice.

Reference to the seller-side sales order behind the invoice.

This helps the seller, buyer, and ERP systems reconcile the invoice against the internal order process.

## What you usually enter here

Internal sales order identifier

Typical valid values include: SO-88421

Optional according to EN 16931-1.

## What goes wrong often

Avoid values like: , AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

## Examples in context

This helps the seller, buyer, and ERP systems reconcile the invoice against the internal order process.

Optional according to EN 16931-1.

## Valid Examples

- SO-88421

## Invalid Examples

- AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

## Related Fields

This helps the seller, buyer, and ERP systems reconcile the invoice against the internal order process.

- [BT-13 Purchase Order Reference](/resources/xrechnung/bt-13-purchase-order-reference)

## 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-14

### Data Type:
text

### Cardinality:
0..1

### Requirement:
Optional

### Max Length:
50 characters

### Since Version:
Optional

## XML Implementation

### UBL 2.1 Syntax
```
/Invoice/cac:OrderReference/cbc:SalesOrderID
```

### CII (UN/CEFACT) Syntax
```
/CrossIndustryInvoice/SupplyChainTradeTransaction/ApplicableHeaderTradeAgreement/ram:SellerOrderReferencedDocument/ram:IssuerAssignedID
```

## Create an XRechnung from your PDF

The converter reads the invoice and shows the fields it found before download, so you can check and correct the values. No PDF? Fill in the XRechnung directly in the form.

- [Convert invoice](/en/pdf-to-xrechnung)
- [Fill in XRechnung in the form](/en/create-xrechnung)

Download requires an account. Subscriptions from €10/month with annual billing (excl. taxes), or €5 per conversion (excl. taxes) without a subscription.

## Why the standard cares about this field

### Business Context
This helps the seller, buyer, and ERP systems reconcile the invoice against the internal order process.

### Legal Requirement
Optional according to EN 16931-1.

## 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)