BR-CO – Conditions and calculations

BR-CO-10: sum of line net amounts (BT-106) does not add up

ErrorEN 16931 business rule (CEN)

Official message

[BR-CO-10]-Sum of Invoice line net amount (BT-106) = Σ Invoice line net amount (BT-131).

Source: CEN EN 16931, version 1.3.16

What the message means

The invoice states a total of all lines that does not match the sum of the individual line net amounts. The recipient re-adds the lines; if the stated sum is off by a single cent, the invoice is arithmetically inconsistent and is rejected. Most of the time rounding is to blame, or a line that was changed after the total had been calculated.

How to fix it

Calculate BT-106 as the sum of all BT-131 (net amount per line), each line amount rounded to two decimals first, and write exactly that value into LineExtensionAmount of the document totals.

Before – invalid

<cac:LegalMonetaryTotal>
  <cbc:LineExtensionAmount currencyID="EUR">140.00</cbc:LineExtensionAmount>
</cac:LegalMonetaryTotal>
<cac:InvoiceLine>
  <cbc:ID>1</cbc:ID>
  <cbc:LineExtensionAmount currencyID="EUR">100.00</cbc:LineExtensionAmount>
</cac:InvoiceLine>
<cac:InvoiceLine>
  <cbc:ID>2</cbc:ID>
  <cbc:LineExtensionAmount currencyID="EUR">50.00</cbc:LineExtensionAmount>
</cac:InvoiceLine>

After – corrected

<cac:LegalMonetaryTotal>
  <cbc:LineExtensionAmount currencyID="EUR">150.00</cbc:LineExtensionAmount>
</cac:LegalMonetaryTotal>
<cac:InvoiceLine>
  <cbc:ID>1</cbc:ID>
  <cbc:LineExtensionAmount currencyID="EUR">100.00</cbc:LineExtensionAmount>
</cac:InvoiceLine>
<cac:InvoiceLine>
  <cbc:ID>2</cbc:ID>
  <cbc:LineExtensionAmount currencyID="EUR">50.00</cbc:LineExtensionAmount>
</cac:InvoiceLine>

Frequently asked

Why is the sum off by just one cent?

Usually each line is rounded differently from the total. The norm requires rounding every line amount to two decimals first, then adding up. That result must appear in BT-106 exactly.

Do document-level discounts belong in BT-106?

No. BT-106 is the plain sum of the lines. Document-level allowances and charges are applied in BT-109.

Also seen when …

Lines were changed or deleted after the total was calculated, without recalculating it.
Rounding per line and rounding of the total differ, for example with quantity discounts.
Line amounts are gross while the total is net, or the other way round.

Fields concerned

BT-106
BT-131

Related rules

BR-CO-13
BR-DEC-09
BR-12

Check your invoice

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Technical details

UBL · Context (XPath): cac:LegalMonetaryTotal
UBL · Schematron test: (xs:decimal(cbc:LineExtensionAmount) = xs:decimal(round(sum(//(cac:InvoiceLine|cac:CreditNoteLine)/xs:decimal(cbc:LineExtensionAmount)) * 10 * 10) div 100))
CII · Context (XPath): //ram:SpecifiedTradeSettlementHeaderMonetarySummation
CII · Schematron test: xs:decimal(ram:LineTotalAmount) = round(xs:decimal(sum(../../ram:IncludedSupplyChainTradeLineItem/ram:SpecifiedLineTradeSettlement/ram:SpecifiedTradeSettlementLineMonetarySummation/ram:LineTotalAmount)) * xs:decimal(100)) div xs:decimal(100)

Explanation written on 14 September 2026