Rule BR-CL-17
VAT category codes must come from UNCL5305
The VAT category on a line or in a VAT breakdown is one of the single letter codes UNCL5305 defines, and the letter has a fixed meaning that the rest of the invoice must agree with.
Business term BT-151 and BT-95, VAT category code. 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 field holds a rate or a rate band rather than a category, so "20", "standard", "reduced" or "TVA20" appears where a single letter belongs. The category and the rate are two different things and this rule is about the first.
- A letter is chosen by guesswork because the meanings are not obvious: K is intra-community supply, AE is reverse charge, G is export outside the EU, O is outside the scope of VAT, Z is zero rated and E is exempt. Several of those describe situations that feel identical from the seller's chair and are not.
- The letter is lowercase, or a multi-letter code is truncated, so "a" arrives where AE belongs.
- A country specific category is used outside the country that defines it. Italy's B, for transferred VAT, is real and is not something to reach for on a French invoice.
What to change
- Send one of the accepted letters exactly: S, Z, E, AE, K, G, O, and the country specific ones only where they apply. Uppercase, no padding.
- Pick the category from the tax treatment, not from the rate. Two lines can both be at zero percent and need different categories, and the rate rules downstream will then fire on the mismatch.
- Keep the category and the rate in two separate fields all the way through your system. Deriving one from the other at export is where most of these failures are born.
- Once the category is right, check the rate rule that belongs to it: each category has its own, and passing this rule only gets you to the next one.
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Rules you are likely to hit next
A document that breaks BR-CL-17 usually breaks one of these too, because the same mapping gap tends to affect neighbouring fields.
Questions people actually ask
- What does BR-CL-17 mean?
- The VAT category on a line or in a VAT breakdown is one of the single letter codes UNCL5305 defines, and the letter has a fixed meaning that the rest of the invoice must agree with.
- Which field does BR-CL-17 apply to?
- BT-151 and BT-95, VAT category code. 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-CL-17?
- 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.