FA(3) field · pre-submission error

Split payment — the P_18A field and Annex 15

An invoice whose total amount due exceeds PLN 15,000 and which covers goods or services from Annex 15 must carry the "mechanizm podzielonej płatności" (split payment) annotation — in FA(3) that's the P_18A field. KSeF doesn't enforce it, because it doesn't know which goods belong to Annex 15 — so it's easy to send an invoice missing the required annotation.

When split payment is mandatory

The "mechanizm podzielonej płatności" annotation is mandatory when both conditions hold:

the total amount due (gross) exceeds PLN 15,000 or its foreign-currency equivalent, and
the invoice includes at least one good or service from Annex 15 of the VAT Act (e.g. steel and steel products, fuels, electronics, car parts, coal).

Basis: Art. 106e sec. 1 item 18a and Art. 108a sec. 1a of the VAT Act, plus the FA(3) Brochure, Section P_18A.

Two fields that must agree

P_18A — the "mechanizm podzielonej płatności" annotation at the invoice level (1 = split payment).
P_12_Zal_15 — a line-level marker flagging an item as Annex-15 goods or services.

The two most common mistakes

Missing the MPP annotation

The invoice exceeds PLN 15,000 and contains Annex-15 goods, but has no P_18A annotation. That breaks Art. 106e sec. 1 item 18a — even though KSeF accepts it.

P_18A = 1 with no line marker

The invoice declares split payment (P_18A = 1) but no line is marked as Annex-15 (P_12_Zal_15). The declaration is internally inconsistent.

Why KSeF doesn't catch it

KSeF validates the XSD structure. It has no mapping of PKWiU codes to Annex 15, so it can't judge whether your goods require split payment at all — it accepts an invoice without the annotation. KSeF Guard ships the Annex-15 list, so it can flag when P_18A is required. This is one of the 107 cases where KSeF Guard catches a non-compliance KSeF does not enforce.

Example

<P_18A>1</P_18A>
...
<FaWiersz>
  <P_7>Steel rod</P_7>
  <P_12_Zal_15>1</P_12_Zal_15>
</FaWiersz>

P_18A = 1 is the "mechanizm podzielonej płatności" annotation for the whole invoice, and P_12_Zal_15 = 1 marks the line carrying Annex-15 goods. (illustrative values)

What KSeF Guard checks

KSeF Guard checks split-payment consistency: whether an above-threshold invoice with Annex-15 goods carries the P_18A annotation, and whether a P_18A declaration is backed by P_12_Zal_15 line markers. See the full rule set in the Rule Explorer.

Related: foreign-currency invoices (P_14_1W). For higher volumes there's batch validation for accounting offices.

Frequently asked questions

When must an invoice carry the split-payment annotation (P_18A)?

When the total amount due exceeds PLN 15,000 (or its foreign-currency equivalent) and the invoice covers goods or services from Annex 15 of the VAT Act. Then the "mechanizm podzielonej płatności" annotation (P_18A) is required, and the relevant lines must be marked with P_12_Zal_15.

What is the P_12_Zal_15 field?

It is a line-level marker indicating that an item is goods or services from Annex 15. If you declare split payment (P_18A = 1), at least one line should carry this marker — otherwise the declaration is internally inconsistent.

Will KSeF reject an invoice without the MPP annotation?

Not necessarily. KSeF does not map PKWiU codes to Annex 15, so it cannot tell whether your goods require split payment — it may accept an invoice without the annotation. The obligation comes from Art. 106e sec. 1 item 18a of the VAT Act, not the schema itself.

What is the threshold for mandatory split payment?

PLN 15,000 total amount due (gross) or its foreign-currency equivalent, for invoices covering Annex-15 goods or services. Below the threshold split payment remains voluntary.

KSeF Guard is a technical tool, not tax advice.

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