Split payment mechanism and KSeF invoices in Poland – what changes for businesses?

The split payment mechanism and KSeF invoices in Poland are becoming an increasingly important practical issue for businesses, accounting departments and finance teams responsible for VAT settlements. Although the split payment mechanism itself is not new, payments for invoices issued through the National e-Invoicing System (KSeF) in Poland will require businesses to pay closer attention to how invoices are identified in the split payment transfer message.

From 1 January 2027, where Polish regulations require KSeF data to be provided for payments relating to structured invoices, it will be important to correctly indicate either the KSeF invoice number or the collective identifier. This will be particularly relevant for payments made under the split payment mechanism.

For companies operating in Poland, this means that preparation for KSeF should not be limited to issuing and receiving structured invoices. Businesses should also review their payment procedures, accounting systems and internal invoice approval workflows. This is especially important for companies that regularly receive invoices subject to mandatory split payment, settle multiple invoices from the same supplier or use finance and accounting systems integrated with online banking.

KSeF does not change the basic principles of the Polish split payment mechanism. The decisive factors remain the provisions of the Polish VAT Act, the invoice value, the status of the parties to the transaction and the type of goods or services purchased. What changes is the technical link between the payment and the structured invoice. For a single invoice, the KSeF invoice number will be important. For a collective payment, the collective identifier generated by the National e-Invoicing System (KSeF) In Poland will be used.

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What is the split payment mechanism in Poland?

The split payment mechanism, referred to in Polish regulations and banking practice as “mechanizm podzielonej płatności” or MPP, is a special method of paying an invoice. The payment is divided into two parts:

• the net amount is transferred to the supplier’s settlement account or settled in another permitted way,
• the VAT amount is transferred to the supplier’s dedicated VAT account.

The buyer makes this payment using a dedicated split payment transfer message provided by a bank or credit union. The transfer message includes, among other things, the VAT amount, the gross amount, the seller’s Tax Identification Number (NIP) and data that allows the payment to be linked to the invoice.

In the existing model, the invoice number has been the key reference. In the case of structured invoices issued through the National e-Invoicing System (KSeF) in Poland, the system-generated KSeF invoice number becomes essential. This number makes it possible to clearly identify the document in Poland’s e-invoicing system.

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When is split payment mandatory in Poland?

The split payment mechanism may be used voluntarily, but in certain cases it is mandatory under Polish VAT rules. In general, mandatory split payment applies when all of the following conditions are met:

• the invoice documents a transaction between taxpayers,
• the total amount due on the invoice exceeds PLN 15,000 or the equivalent of this amount,
• the invoice covers goods or services listed in Annex 15 to the Polish VAT Act.

If these conditions are met, the invoice should include the wording “mechanizm podzielonej płatności” (“split payment mechanism”). However, the buyer’s obligation to apply split payment does not depend solely on whether the seller has marked the invoice correctly. The buyer should independently assess whether the goods or services purchased are subject to mandatory split payment.

In practice, this means that the absence of the split payment wording on the invoice does not always release the buyer from the obligation to apply split payment. At the same time, marking an invoice as subject to split payment should not replace a proper analysis of whether the statutory conditions are actually met.

Where there are doubts about transaction classification, VAT rates, documentation obligations or the correct application of split payment, businesses may benefit from professional tax advisory in Poland, especially if they carry out many high-value transactions or operate in sectors covered by Annex 15 to the Polish VAT Act.

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Does KSeF change the rules for using split payment?

KSeF does not change the essence of the split payment mechanism. The payment is still divided into the net amount and the VAT amount. The core conditions for mandatory split payment also remain unchanged.

The main change concerns the way the invoice is identified in the payment process. For structured invoices issued through KSeF, businesses will need to pay particular attention to the number identifying the invoice in the system. This number is not the same as the invoice number assigned by the seller in its own accounting system.

The KSeF number is assigned by the National e-Invoicing System and functions as a technical identifier of the document. From 1 January 2027, correct use of the KSeF number or collective identifier will be important for payments relating to structured invoices, including payments made under the split payment mechanism. Businesses should therefore verify whether their accounting systems, invoice approval procedures and payment processes are ready to work with this data.

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Invoice number vs KSeF number – what is the difference?

In practice, businesses may have to deal with several identifiers for the same invoice. The most important are:

• the invoice number assigned by the seller,
• the number identifying the invoice in KSeF,
• the collective KSeF identifier, if the payment covers more than one structured invoice.

The invoice number assigned by the seller is part of the accounting document and reflects the seller’s internal numbering system. The KSeF number, on the other hand, is assigned by the system after the structured invoice is accepted. For payments relating to structured invoices, the KSeF number will become the key identification reference.

For finance teams, this means that data must remain consistent across the invoice, accounting system, online banking system and VAT records. Errors in this area may make it difficult to automatically match payments with invoices and, where large volumes of documents are processed, may lead to unnecessary explanations and corrections.

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How to pay a single KSeF invoice using split payment

If a business pays one structured invoice subject to split payment, it should use the dedicated split payment transfer message. In this message, the following data should generally be indicated:

• the amount corresponding to all or part of the VAT shown on the invoice,
• the amount corresponding to all or part of the gross sales value,
• the number identifying the invoice in KSeF,
• the number by which the seller is identified for tax purposes, such as the Tax Identification Number (NIP).

If the payment concerns only part of the amount due, the amounts indicated in the transfer message should correspond to the part being paid. In practice, this requires the business to determine precisely what part of the VAT relates to the partial payment.

It is also important to remember that the split payment transfer message applies to payments in Polish zloty. For invoices issued in foreign currencies, businesses must follow Polish VAT conversion rules and ensure that the settlement is properly adapted to banking and accounting requirements.

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Collective split payment for several KSeF invoices

One important practical issue is the possibility of paying several invoices with one split payment transfer. The Polish VAT Act allows this where one supplier or service provider has issued more than one invoice to the taxpayer within a period of not less than one day and not more than one month.

For structured invoices issued through KSeF, a collective payment may cover selected invoices issued by one supplier or service provider during that period. This means that the business does not have to include all invoices from a given supplier for the relevant period in one transfer. It may choose only the invoices it wants to pay, provided that the statutory conditions are met.

This is an important difference compared with invoices issued outside KSeF. For invoices other than structured invoices, the collective transfer message covers all invoices from one supplier or service provider for the given period, and the payment period is entered in the field intended for the invoice number.

For KSeF invoices, the payment technique is different. Instead of entering a period or individual invoice numbers in the transfer message, the business indicates the collective identifier assigned by the National e-Invoicing System (KSeF).

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What is a collective KSeF identifier?

A collective KSeF identifier is a system-generated reference for a selected set of structured invoices. It allows one payment to be linked to several invoices issued through KSeF.

In practice, the business selects the invoices to be covered by one payment, and a collective identifier is then generated for that set. This identifier aggregates the KSeF numbers of the invoices included in the payment. As a result, the transfer message does not need to include each invoice number separately.

The collective identifier will be particularly important for businesses that receive many invoices from the same suppliers, make recurring payments or use collective payments for purchase invoices. It may simplify the payment process, but it requires the company to correctly determine which invoices are included in a specific payment.

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How to make a collective split payment transfer for KSeF invoices

Before making a collective split payment for structured invoices, the company should first determine which invoices from a given supplier are to be paid with one transfer. These invoices should be issued by the same supplier or service provider and fall within a period of not less than one day and not more than one month.

The company should then verify whether the invoices are subject to mandatory split payment or whether it wants to apply split payment voluntarily. If the mandatory split payment obligation applies only to some items on the invoice, the VAT amount and the amount payable under this mechanism must be calculated correctly.

For the selected set of invoices, the company should generate a collective KSeF identifier. This identifier will be used in the transfer message instead of the individual invoice numbers. The split payment transfer message should then include:

• the total gross payment amount,
• the VAT amount corresponding to the total VAT from the invoices covered by the payment, or the relevant part of that amount,
• the seller’s Tax Identification Number (NIP),
• the collective KSeF identifier.

It is advisable to keep internal documentation confirming which invoices were covered by a given collective identifier. This is important for payment control, accounting reconciliation and possible explanations with the supplier.

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Example: paying several KSeF invoices with one split payment transfer

A company receives five structured invoices issued in KSeF from one supplier. Each invoice documents the purchase of goods listed in Annex 15 to the Polish VAT Act, and the total amount due on each invoice exceeds PLN 15,000. The company wants to pay three of these invoices with one transfer.

In this case, the company may use a collective split payment transfer, provided that the selected invoices were issued by the same supplier within a period of not less than one day and not more than one month. The company does not have to include all five invoices in the transfer. It may select three documents, generate a collective KSeF identifier for them and then enter that identifier in the split payment transfer message.

The transfer message should include the total gross amount of the invoices being paid and the total VAT amount resulting from those documents. The field used to identify the invoice should not contain the individual invoice numbers or the payment period. The correct reference is the collective identifier.

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KSeF invoices and non-KSeF invoices – differences in collective payments

Businesses should distinguish between two situations: collective payments for structured invoices and collective payments for invoices issued outside KSeF.

For invoices outside KSeF, the split payment transfer message covers all invoices issued by one supplier or service provider within the given period. The period may not be shorter than one day or longer than one month. The period for which the payment is made is entered in the field intended for the invoice number.

For structured invoices issued in KSeF, the transfer message may cover selected invoices issued by one supplier within the required period. There is no obligation to include all invoices from that period in the transfer. The collective KSeF identifier is indicated in the transfer message.

This difference has practical significance because it affects payment planning. Companies should adapt their internal procedures so that people responsible for payments know when to indicate a period, when to use the KSeF number and when to use the collective identifier.

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Can every KSeF invoice be marked as subject to split payment?

In practice, some businesses may consider marking all structured invoices as subject to split payment in order to simplify accounting processes and reduce the risk of errors. This approach should be treated with caution.

Polish VAT regulations specify when an invoice should include the wording “mechanizm podzielonej płatności”. This obligation applies to invoices that meet the statutory conditions, including the PLN 15,000 threshold and the supply of goods or services listed in Annex 15 to the Polish VAT Act.

Tax interpretations may indicate that adding extra information to an invoice does not necessarily constitute a breach of invoicing rules. However, this does not mean that marking every invoice as subject to split payment is operationally neutral. It may create misunderstandings for buyers, make it more difficult to assess which transactions are actually subject to mandatory split payment and disrupt automated payment processes.

From a tax security perspective, the better approach is to classify transactions correctly and apply the split payment marking where it is required by law. If a company wants to adopt a simplified operational procedure, it should first assess the tax, accounting and system-related consequences.

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What should the buyer check before paying a KSeF invoice?

The buyer should not limit the verification process to checking whether the invoice includes the split payment wording. Before making payment, it is worth verifying:

• whether the invoice value exceeds PLN 15,000 or its equivalent,
• whether the invoice covers goods or services listed in Annex 15 to the Polish VAT Act,
• whether the payment concerns the whole invoice, part of the invoice or several invoices,
• whether the invoice is a structured invoice issued in KSeF,
• whether the KSeF number or the collective identifier should be used,
• whether the VAT amount in the transfer message corresponds to the payment covered by split payment.

In larger organisations, these elements should be built into the invoice workflow. This is particularly important where purchasing, substantive approval, accounting and payment are handled by different people or departments.

If a company uses external accounting support, it should agree with its accounting provider or tax adviser what data will be exchanged, who will verify the split payment obligation and how collective payments will be documented. In this area, accounting services in Poland may help businesses maintain a consistent process for bookkeeping, VAT settlements and e-invoicing.

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Split payment mechanism extended until 2028

The split payment mechanism remains an important element of the Polish VAT system. Its application has been extended, which means that businesses should treat split payment as a permanent part of tax and payment processes rather than as a temporary solution.

We discussed the implications of this decision for taxpayers in more detail in the article: Application of the split payment mechanism in Poland extended until 2028 – what does this mean for taxpayers?

In the context of KSeF, this means that companies should look at split payment and e-invoicing together. Both areas will become increasingly connected at the level of data, accounting systems and controls over the correctness of VAT settlements.

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Key points for businesses using KSeF and split payment in Poland

The split payment mechanism and KSeF invoices require businesses to combine tax, accounting and technical knowledge. KSeF does not change the basic conditions for mandatory split payment, but it gives new practical importance to the KSeF number and the collective identifier used in payments.

The key rules are as follows:

• mandatory split payment still applies to transactions meeting the conditions set out in the Polish VAT Act,
• for a single structured invoice, the KSeF number is the key reference,
• for a collective payment covering several KSeF invoices, the collective identifier is used,
• a collective payment for structured invoices may cover selected invoices from one supplier for a period of not less than one day and not more than one month,
• companies should adapt payment procedures, accounting systems and document workflows to the new identification data.

For businesses operating in Poland, the most important step is practical preparation. Correct use of split payment in KSeF is not only a matter of knowing the regulations. Companies must also ensure that the KSeF number, collective identifier, VAT amounts and supplier data are correctly transferred between systems and the people responsible for settlements.

getsix® supports businesses in the areas of accounting, VAT settlements and tax compliance processes in Poland. If your company needs support in reviewing payment procedures, correctly settling VAT or managing ongoing accounting processes, you can consult the process with our team of tax and accounting specialists. Contact us.

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