# BT-149 Item Price Base Quantity

The quantity on which the item net price is based.

## Quick answer

> **Line items**: The goods or services on each invoice line, including quantities, prices, and VAT.

- [Validate XML](/en/xrechnung-validator?source=resource&bt=BT-149)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&bt=BT-149)

## In plain language

Describes how the invoice line price is derived, including base quantity and any price-level discount, so automated checks can recalculate line totals.

## What you usually enter here

Positive decimal quantity

Typical valid values include: 1, 100

Defined by EN 16931 for line price calculation data; required fields must satisfy the listed BR and Peppol calculation constraints.

## Where the field sits

BT-149 belongs to the Lines part of the invoice. UBL 2.1 Syntax: Invoice › cac:InvoiceLine › cac:Price › cbc:BaseQuantity. CII (UN/CEFACT) Syntax: rsm:CrossIndustryInvoice › rsm:SupplyChainTradeTransaction › ram:IncludedSupplyChainTradeLineItem › ram:SpecifiedLineTradeAgreement › ram:NetPriceProductTradePrice › ram:BasisQuantity or rsm:CrossIndustryInvoice › rsm:SupplyChainTradeTransaction › ram:IncludedSupplyChainTradeLineItem › ram:SpecifiedLineTradeAgreement › ram:GrossPriceProductTradePrice › ram:BasisQuantity. If BT-149 is present in both price locations, the quantities must match. If BT-150 is present on NetPriceProductTradePrice, it must also be present on GrossPriceProductTradePrice with the same unit code (BR-TMP-3).

## What goes wrong often

Avoid values like: 0, -1

Relevant rule codes: PEPPOL-EN16931-R120, PEPPOL-EN16931-R121

## Valid Examples

- 1
- 100

## Invalid Examples

- 0
- -1

## Related Fields

- [BT-146 Item Net Price](/resources/xrechnung/bt-146-item-net-price)
- [BT-150 Item Price Base Quantity Unit Code](/resources/xrechnung/bt-150-item-price-base-quantity-unit-code)

## 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-149

### Data Type:
quantity

### Cardinality:
0..1

### Requirement:
Optional

## XML Implementation

### UBL 2.1 Syntax
```
/Invoice/cac:InvoiceLine/cac:Price/cbc:BaseQuantity
```

### CII (UN/CEFACT) Syntax
```
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:IncludedSupplyChainTradeLineItem/ram:SpecifiedLineTradeAgreement/ram:NetPriceProductTradePrice/ram:BasisQuantity
```

## Validation Rules

### PEPPOL-EN16931-R120
PEPPOL-EN16931-R120

### PEPPOL-EN16931-R121
PEPPOL-EN16931-R121

## Check whether your XRechnung sets BT-149 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 PEPPOL-EN16931-R120. 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)