Rule BR-DEC-13
The invoice total VAT amount may have at most two decimals
The total VAT on the invoice is stated with no more than two decimal places, in the currency of the invoice.
Business term BT-110, Invoice total VAT amount. Source: EN 16931. Our wording, not the normative text, which is published in the Peppol BIS Billing 3.0 rule list (EN 16931 rules) and was checked against it on 2026-08-16.
Why it fires on invoices that look fine
Almost nobody hits this rule because they forgot the field exists. They hit it because something between their system and the document dropped it, changed its shape, or filled it with a value that is right somewhere else. These are the causes worth checking first.
- The VAT is the raw product of a rate and a taxable base, and that product almost never lands on two decimals: 20 percent of 33.33 is 6.666, and nothing about the inputs looks wrong.
- VAT was computed per line at full precision and then summed, so several unrounded fractions accumulate into a total with three or four decimals.
- A rate with its own decimals, such as 5.5 percent, multiplies an already awkward base.
- The total was assembled from a VAT breakdown whose category amounts were each rounded, but the sum was recomputed from the unrounded values rather than from the rounded ones.
What to change
- Round the VAT amount to two decimals per category in the breakdown, then make the invoice total VAT the sum of those rounded figures. Summing first and rounding after gives a different number and breaks the consistency rules downstream.
- Decide once whether your VAT is computed per line or per category and apply that everywhere, because the two methods legitimately differ by a cent and mixing them produces a document that disagrees with itself.
- Check what your tax authority requires: several mandate rounding per VAT rate rather than per line, and that choice is not ours or the norm's to make for you.
- Use a decimal type rather than binary floating point for the tax calculation, so the value you round is the value you meant.
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Rules you are likely to hit next
A document that breaks BR-DEC-13 usually breaks one of these too, because the same mapping gap tends to affect neighbouring fields.
Questions people actually ask
- What does BR-DEC-13 mean?
- The total VAT on the invoice is stated with no more than two decimal places, in the currency of the invoice.
- Which field does BR-DEC-13 apply to?
- BT-110, Invoice total VAT amount. That is the name the semantic model uses, which is what you search for in your own system's mapping when the identifier alone does not tell you which field to look at.
- Does our validator check BR-DEC-13?
- Yes. Paste your invoice data into the free validator and it reports this rule with the value it actually saw, without the document leaving your browser.