# BR-53: Add the VAT total in the VAT accounting currency

When `cbc:TaxCurrencyCode` is given, the document needs a second tax total whose `cbc:TaxAmount` is stated in that currency.

- Layer: EN 16931
- Severity: fatal (the document is invalid)
- Topics: VAT, Totals
- Official definition: https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/BR-53/
- Explanation last updated: 2026-09-24

## The short answer

`BR-53` fails when the document declares a VAT accounting currency in `cbc:TaxCurrencyCode` and no `cac:TaxTotal/cbc:TaxAmount` has that currency in its `currencyID`. Add a second `cac:TaxTotal` directly under the root that holds only a `cbc:TaxAmount`, with `currencyID` set to the accounting currency and the VAT total converted into it.

If the seller accounts for VAT in the invoice currency, the fix runs the other way: remove `cbc:TaxCurrencyCode`. It is optional, and belongs only on a document whose VAT must be accounted for in a currency other than the one it is issued in.

## What the rule checks

The rule runs once on the document root. For the `cbc:TaxCurrencyCode` there, it looks for a `cbc:TaxAmount` that is a direct child of a `cac:TaxTotal` and whose `currencyID` is the same code. Tax amounts inside a `cac:TaxSubtotal` do not count, and the order of the tax totals does not matter.

A document without `cbc:TaxCurrencyCode` gives the rule nothing to look for, so it passes.

Only the currency is matched. The amount is not examined: no rule converts the invoice VAT total or checks an exchange rate, and when tried, an accounting-currency total of 0.00 beside 5.00 of VAT in the invoice currency passed every layer.

The code and the `currencyID` are matched exactly as written. When tried, a `cbc:TaxCurrencyCode` with spaces around `EUR`, beside a correct EUR total, reported this rule and nothing else. A lower-case `eur` also brought `BR-CL-05`, the currency code list rule, and `PEPPOL-EN16931-R055`.

| Term | Meaning | UBL element |
|---|---|---|
| BT-6 | VAT accounting currency code | `cbc:TaxCurrencyCode` |
| BT-111 | Invoice total VAT amount in accounting currency | `cac:TaxTotal/cbc:TaxAmount (in the tax total without cac:TaxSubtotal, currencyID equal to BT-6)` |
| BT-110 | Invoice total VAT amount | `cac:TaxTotal/cbc:TaxAmount (in the tax total that holds the VAT breakdown)` |

## How an integration ends up here

Possible causes, from the shape of the rule rather than from measured usage:

- The accounting currency code is filled from a company setting on every document, while the converted VAT total is written only when a conversion was actually made.
- The serialiser writes a single `cac:TaxTotal` and has no place for a second one, so the converted figure is lost.
- The converted amount is written with the invoice currency, or another currency, in its `currencyID`. When tried with the invoice currency, `BR-CO-15` came too, because it expects exactly one VAT total in the invoice currency.
- The code is written in lower case or with padding, so it no longer matches the `currencyID` of the amount.

## How to fix it

1. Decide whether the document needs a VAT accounting currency at all. If the seller accounts for VAT in the invoice currency, remove `cbc:TaxCurrencyCode` and stop here.
2. Otherwise take the invoice VAT total, the `cbc:TaxAmount` of the `cac:TaxTotal` that holds the breakdown, and convert it into the accounting currency at the rate your VAT accounting requires. The rate comes from your accounting rules; the validator does not check it.
3. Add a second `cac:TaxTotal` directly under the root containing only `cbc:TaxAmount`, with `currencyID` equal to the `cbc:TaxCurrencyCode` value and the converted amount rounded to two decimals. A third decimal brings `UBL-DT-01`. Give this total no `cac:TaxSubtotal`: the breakdown stays in the invoice currency.
4. Write the code and the `currencyID` as the same upper-case ISO 4217 code without spaces, and keep the converted amount on the same side of zero as the invoice VAT total, which `PEPPOL-EN16931-R055` checks.

## Before and after

These are fragments, not complete documents. The complete synthetic documents they come from are linked below.

Fragment of the failing invoice: EUR is declared as the accounting currency, but the only tax total is in GBP

```xml
<cbc:DocumentCurrencyCode>GBP</cbc:DocumentCurrencyCode>
<cbc:TaxCurrencyCode>EUR</cbc:TaxCurrencyCode>
<!-- buyer reference and parties omitted from this fragment -->
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="GBP">5.00</cbc:TaxAmount>
  <!-- VAT breakdown omitted from this fragment -->
</cac:TaxTotal>
<cac:LegalMonetaryTotal>
  <!-- monetary totals omitted from this fragment -->
</cac:LegalMonetaryTotal>
```

Fragment of the corrected invoice: a second tax total states the VAT in EUR

```xml
<cbc:DocumentCurrencyCode>GBP</cbc:DocumentCurrencyCode>
<cbc:TaxCurrencyCode>EUR</cbc:TaxCurrencyCode>
<!-- buyer reference and parties omitted from this fragment -->
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="GBP">5.00</cbc:TaxAmount>
  <!-- VAT breakdown omitted from this fragment -->
</cac:TaxTotal>
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="EUR">5.80</cbc:TaxAmount>
</cac:TaxTotal>
<cac:LegalMonetaryTotal>
  <!-- monetary totals omitted from this fragment -->
</cac:LegalMonetaryTotal>
```

The corrected invoice has a second `cac:TaxTotal` holding only a `cbc:TaxAmount` of 5.80 in EUR; the failing one declares EUR as its accounting currency and has no amount in it. Two Peppol rules report the same gap. `PEPPOL-EN16931-R054` fires because a declared accounting currency needs exactly one tax total without a breakdown and there is none. `PEPPOL-EN16931-R055` fires because it compares the signs of the two VAT totals and cannot find the EUR one. Restoring the EUR total clears all three. The 5.80 is an illustrative figure: nothing checks it against the 5.00 in GBP.

### What the validator reported

- The failing invoice reports **BR-53**, [PEPPOL-EN16931-R054](https://ironfang.uk/docs/finance/rules/PEPPOL-EN16931-R054.md) and [PEPPOL-EN16931-R055](https://ironfang.uk/docs/finance/rules/PEPPOL-EN16931-R055.md). The corrected document passes every layer with no findings.
  - [Download the failing XML](https://ironfang.uk/finance/rule-examples/BR-53-invalid.xml)
  - [Download the corrected XML](https://ironfang.uk/finance/rule-examples/tax-currency-valid.xml)

Recorded on phive 12.1.0 / phive-rules-peppol 4.5.6 / Saxon-HE 12.10, the engine behind the free validator, using synthetic data. A recorded result is regression evidence for these documents; it is not a certification.

## Where it applies

- Applies to UBL `Invoice` and `CreditNote`. A credit note declaring EUR with no EUR tax total reported the same three rules when tried.
- Reported by the EN 16931 layer. The Peppol layer adds `PEPPOL-EN16931-R054` and `PEPPOL-EN16931-R055` for the same gap, and `PEPPOL-EN16931-R005` when the declared accounting currency is the invoice currency.
- The accounting-currency amount is left out of the Peppol requirement that every `currencyID` equals the invoice currency, because it sits in a tax total without a breakdown. A breakdown in the accounting currency is not accepted; that case is described under `PEPPOL-EN16931-R054`.
- A `cbc:TaxCurrencyCode` that is not a valid ISO 4217 code is reported by `BR-CL-05`.

## Related rules

- [PEPPOL-EN16931-R054 requires exactly one tax total without a breakdown when the accounting currency is declared, and none otherwise](https://ironfang.uk/docs/finance/rules/PEPPOL-EN16931-R054.md)
- [PEPPOL-EN16931-R055 checks that this amount has the same sign as the VAT total in the invoice currency](https://ironfang.uk/docs/finance/rules/PEPPOL-EN16931-R055.md)
- [PEPPOL-EN16931-R005 rejects an accounting currency that is the same as the invoice currency](https://ironfang.uk/docs/finance/rules/PEPPOL-EN16931-R005.md)
- [PEPPOL-EN16931-R051 requires the invoice currency on every other amount in the document](https://ironfang.uk/docs/finance/rules/PEPPOL-EN16931-R051.md)

## Scope and source

Written for Peppol BIS Billing 3.0.21 (May 2026), EN 16931 1.3.16, as applied to UBL 2.1 Invoice and CreditNote documents. Other profiles, syntaxes and releases can define this identifier differently. Guidance version 2026-09-24.1: source checked 2026-09-24, explanation last updated 2026-09-24.

[The official definition of BR-53](https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/BR-53/) carries the normative wording and test. This page is our explanation of it, not a copy.

Guidance does not change the engine verdict. Fixing this finding does not mean the document passes every layer, and validation does not certify legal or tax compliance or transmit a document over Peppol.

## Links

- [This rule as a web page](https://ironfang.uk/docs/finance/rules/BR-53)
- [Free Peppol invoice validator](https://ironfang.uk/tools/peppol-validator)
- [Rule index](https://ironfang.uk/docs/finance/rules.md)
- [Ironfang Finance API docs](https://ironfang.uk/docs/finance)
- The same rule is available to MCP clients as the tool `finance.rule.get` on https://mcp.ironfang.uk/mcp