Split payment in KSeF: how to fill in P_18A

On an FA(3) invoice in KSeF (Krajowy System e-Faktur, Poland's National e-Invoicing System), the split payment mechanism (MPP, mechanizm podzielonej płatności) is marked in field P_18A of the Adnotacje section: enter 1 when the total amount due exceeds PLN 15,000 (or its equivalent in a foreign currency), the invoice covers goods or services listed in annex 15 to the VAT Act and the supply is made to a taxpayer, and 2 in every other case. The field is mandatory on every invoice, including when MPP doesn't apply to you.

Legal position as of 22 October 2026.

When to enter 1 and when 2

All three conditions must be met at the same time:

• the total amount due exceeds PLN 15,000; on a standard invoice that is the amount in field P_15 (exactly PLN 15,000.00 does not exceed the threshold),
• the invoice covers a supply of goods or services listed in annex 15 to the VAT Act,
• the supply is made to a taxpayer ("na rzecz podatnika").

That is how the schema annotation for P_18A reads, and it follows art. 106e ust. 1 pkt 18a of the VAT Act. FA(3) schema, element P_18A FA(3) information sheet, p. 55

If any of them is missing, you enter 2. On advance, final settlement and corrective invoices, the schema gives P_15 a different meaning (the amount paid, the amount still due, the correction amount), and MF sources don't say how to count the threshold in those cases. The VAT Act applies art. 108a ust. 1–1b to advance payments "accordingly" (ust. 1c; art. 19a ust. 8), and the transfer message carries the word "zaliczka" (advance) instead of the invoice number. The schema annotation for the field also repeats the words "mechanizm podzielonej płatności" (split payment mechanism), and in KSeF their equivalent is the value 1. FA(3) schema, element P_18A

An example: a wholesaler, a client of Pani Krystyna (an accountant), sells annex 15 goods to a business (a VAT taxpayer) on an invoice with a total amount due of PLN 18,450. P_18A = 1. The same wholesaler issues an invoice for PLN 12,300 for the same goods: P_18A = 2. Ania, a graphic designer, invoices PLN 20,000 for logo design. The amount is above the threshold, but if her service isn't in annex 15, she enters 2.

We don't reproduce the full list of annex 15 items here. The FA(3) information sheet refers to its items when describing GTU codes: they include some electronics, waste and metals.

Foreign currency invoices

The PLN 15,000 threshold also applies to invoices in euro or dollars. You convert the amount into złoty using the same rules you apply to the taxable amount (so says the annotation to P_18A in the schema). Those rules are in art. 31a of the VAT Act. As a rule it is the NBP (National Bank of Poland) average rate from the last business day before the tax point, but the provision has exceptions, including the option to use the ECB rate and a different date when the invoice is issued before the tax point.

An invoice to a business for EUR 4,000 for annex 15 goods at an example rate of PLN 4.25 gives PLN 17,000. That is above the threshold, so P_18A = 1. At an example rate of PLN 3.70 it would come to PLN 14,800, and 2.

Mandatory and voluntary MPP

As a rule, MPP is voluntary: the Act says that when paying, taxpayers "may apply" split payment (art. 108a ust. 1 of the VAT Act). It is mandatory when paying for annex 15 goods and services if the invoice exceeds PLN 15,000 (art. 108a ust. 1a; with exceptions in art. 108a ust. 1d–1e, e.g. offsetting), and the seller must then accept payment by MPP for an invoice covered by art. 106e ust. 1 pkt 18a (ust. 1b). For paying in breach of ust. 1a, the Act provides a sanction in art. 108a ust. 7. A seller who issues an invoice in breach of art. 106e ust. 1 pkt 18a faces an additional liability of 30% of the tax on the annex 15 items (art. 106e ust. 12); it does not apply if that tax was paid by MPP (ust. 13). The art. 108a ust. 7 sanction concerns how you pay, not whether the transfer carries a KSeF number. VAT Act, art. 108a (Dz.U. 2026 item 1263)

P_18A describes only the mandatory case and is not a free choice: the schema and the information sheet say to enter 1 when all three conditions are met and, "otherwise, the value 2" (information sheet, pp. 55–56). There is no separate value for voluntary MPP. A buyer who is a taxpayer and received an invoice showing VAT may use MPP when paying it even if P_18A = 2 (art. 108a ust. 1).

Line-level markers and GTU codes

Besides P_18A, the schema has two optional markers for individual items:

• P_12_Zal_15 in an invoice line (FaWiersz): value 1 for goods or services from annex 15,
• P_12Z_Zal_15 in an order line of an advance invoice (ZamowienieWiersz), with the same meaning.

You can leave out both, and neither replaces P_18A. The information sheet says to mark P_12_Zal_15 = 1 "regardless of whether the transaction is subject to mandatory split payment or not", so the marker doesn't depend on the value of P_18A. FA(3) information sheet, pp. 93–94 and 139

GTU codes are a separate matter. GTU_05, GTU_06 and GTU_08 cover, among others, annex 15 goods, but the information sheet describes GTU on the invoice as optional, and the schema refers to the JPK_VAT regulation for them. None of the sources we checked says that a GTU code forces P_18A = 1. The value of P_18A depends on the threshold, annex 15 and a supply to a taxpayer. FA(3) information sheet, pp. 94–95

What the law and MF leave open

• Mixed invoices. When only some items are from annex 15, MF materials don't tell us whether the threshold counts against the whole total amount due or only those items. The schema speaks of the invoice's "total amount due" where the invoice "covers" such goods.
• Corrections. We found no description of how to set P_18A on a corrective invoice, especially when the correction moves the amount across the PLN 15,000 threshold. The correction mechanism itself is covered in our post on the corrective invoice in KSeF.

For a mixed invoice or a correction across the threshold, the answer depends on the specific transaction, so ask a tax adviser.

MPP transfers and the KSeF number from 2027

For payments made from 1 January 2027, the MPP transfer message for a KSeF invoice carries its KSeF number instead of the invoice number (art. 108a ust. 3 pkt 3). The details, including the collective identifier for several invoices, are in our post on the KSeF number in a bank transfer.

For developers: P_18A in XML

P_18A takes only 1 or 2 and sits in a fixed position: after P_18, before Zwolnienie. An Adnotacje fragment for an invoice subject to mandatory MPP:

<Adnotacje>
  <P_16>2</P_16>
  <P_17>2</P_17>
  <P_18>2</P_18>
  <P_18A>1</P_18A>
  <Zwolnienie>
    <P_19N>1</P_19N>
  </Zwolnienie>
  <NoweSrodkiTransportu>
    <P_22N>1</P_22N>
  </NoweSrodkiTransportu>
  <P_23>2</P_23>
  <PMarzy>
    <P_PMarzyN>1</P_PMarzyN>
  </PMarzy>
</Adnotacje>

A missing P_18A is a validation error, not "no MPP". The other fields in this section and the usual mistakes with them are covered in the most common FA(3) validation errors.

If you have an XML file and want to check that Adnotacje is complete, drop it into the validator. It reports a missing P_18A, but doesn't check whether you picked the right value for the threshold and annex 15.