Rule BR-O-05
A line not subject to VAT must carry no VAT rate at all
On a line whose category is not subject to VAT, the rate field is absent entirely. Not zero: absent.
Business term BT-152, Invoiced item VAT rate (with BT-151, category code O). Source: EN 16931. Our wording, not the normative text, which is published in the Peppol BIS Billing 3.0 rule list 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.
- A rate of 0 was sent, which looks equivalent and is not. Zero says VAT applies at a rate of zero; category O says VAT does not apply at all, and the two are different statements to a tax authority.
- The data model forces a number, so the exporter has nowhere to express absence and writes 0 as the closest thing. This is the most common cause, and it is a modelling problem rather than a data-entry one.
- The category was chosen for an out-of-scope charge, such as a disbursement recovered at cost, while the template kept filling in the rate.
What to change
- Omit the VAT rate field on those lines. In JSON that means leaving it out, not sending null and not sending 0.
- If your invoicing system cannot omit it, that is worth fixing at the source: the same limitation will misstate every out-of-scope line you ever issue.
- Check the category is really right first. O is narrower than people expect, and an exempt supply (E) or a zero rated one (Z) is often what was actually meant.
The validator runs in your browser. Nothing is uploaded, and you can confirm that yourself with the network panel open.
Rules you are likely to hit next
A document that breaks BR-O-05 usually breaks one of these too, because the same mapping gap tends to affect neighbouring fields.
Questions people actually ask
- What does BR-O-05 mean?
- On a line whose category is not subject to VAT, the rate field is absent entirely. Not zero: absent.
- Which field does BR-O-05 apply to?
- BT-152, Invoiced item VAT rate (with BT-151, category code O). 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-O-05?
- 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.