Running a business today involves ever more frequent use of electronic payments. Business owners regularly receive bank transfer confirmations that document the transactions they have carried out. This raises an important question: can these documents be used in the company's accounts?
Using bank payment confirmations as accounting documents needs to be discussed in detail against the rules in force. The key here is the regulation on keeping the KPiR (tax revenue and expense ledger) (from 1 January 2026 – the Regulation of the Minister of Finance and Economy of 6 September 2025, Journal of Laws (Dz.U.) 2025, item 1299), which sets out precisely which documents can be the basis for accounting entries.
Basic rules for documenting transactions in the KPiR
Keeping the KPiR is subject to strict legal rules that determine how business transactions are documented. Under the regulation, all entries in the ledger must be made in Polish and in Polish currency (§ 6(1) of the regulation), and the ledger must be kept reliably and without defects (§ 4(1)). The same requirements apply to warehouse documents – we describe when to record a WZ goods issue note.
Entries in the KPiR must be made on the basis of correct and reliable accounting documents. Every document on which an entry is based must meet specific formal and substantive requirements under the KPiR regulation
The basic accounting document in a business is the invoice, which is the main source of information about the transactions carried out. This does not mean, however, that it is the only document on which accounting entries can be based. The rules provide for a number of other documents that can be used as accounting evidence in certain situations.
The KPiR regulation sets out in detail which documents can be treated as special types of accounting evidence. This catalogue includes a variety of documents which, depending on the nature of the business transaction, may be a proper basis for an accounting entry. We book such documents in the KPiR of clients who use our accounting services.
Payment confirmation as evidence of bank charges
An analysis of the KPiR regulation shows that payment confirmations can be used in certain situations. Particularly important is the rule on documenting bank charges, which refers directly to confirmations of bank transactions.
The KPiR regulation expressly states that special types of accounting evidence include, among others, evidence of postal and bank charges (§ 7(2) of the regulation). This rule is fundamental to whether bank transfer confirmations can be used as accounting documents. Each such document also needs a number, and numbering accounting documents in the KPiR follows its own rules.
A bank transfer confirmation can be accounting evidence for the bank charges incurred. If a bank transaction carries a commission or fee, this cost can be booked directly on the basis of the payment confirmation generated by the banking system
In practice, this means that when a business owner incurs costs for bank commissions, transfer fees or other bank charges, they can use the bank transaction confirmation as the basis for booking these expenses in the KPiR.
The key point, however, is that the rule on evidence of bank charges covers the bank charges themselves, not the full value of the transaction. This means that a transfer confirmation can be used to document the cost of a bank commission but, as a rule, does not replace the invoice documenting the underlying business transaction – the exceptions are discussed later in this article.
Requirements for accounting documents
For a document to be treated as accounting evidence, it must meet specific formal and substantive requirements. The KPiR regulation sets out precisely what a document must contain to be the basis for an accounting entry.
The basic requirements for accounting documents other than invoices (§ 6(3)(3) of the regulation) include the following elements:
- Reliable identification of the issuer or of the parties to the business transaction
- The date the document was issued and the date or period of the business transaction
- The subject of the business transaction, its value and quantity
- Signatures of the persons authorised to document business transactions properly
- A number or other marking that links the document to the accounting entries
Accounting documents must contain all the elements required by the KPiR regulation. The absence of any of them may undermine the use of the document as the basis for an entry in the KPiR
For bank payment confirmations, check whether the document contains all the required elements. Modern banking systems generate transaction confirmations that usually contain the basic information about the transaction, but they may not meet all the requirements for accounting documents.
Identifying the subject of the business transaction and its value can be particularly problematic. A bank transfer confirmation shows the amount transferred, but may not contain detailed information about the nature of the business transaction for which the payment was made.
Limits on using bank confirmations
Although the rules allow payment confirmations to be used as accounting documents, there are significant limits on their use. The most important is the principle that the invoice takes precedence as the basic accounting document in transactions between businesses.
The tax authorities consistently emphasise that the invoice remains the basic accounting document in business relations. A bank payment confirmation cannot be treated as a universal substitute for an invoice when the invoice is missing.
A bank payment confirmation cannot replace an invoice in transactions where the taxpayer has a legal basis to receive that document. The invoice retains its primary role as an accounting document and cannot be freely replaced by other accounting evidence
The tax authorities state in their rulings that an entry in the ledger should, as a rule, be based on an invoice, and on other evidence only if it contains all the data required by the regulation (e.g. the Director of KIS (National Tax Information) in the ruling of 11 October 2024, 0112-KDIL2-2.4011.594.2024.2.MM). That is why, where a transaction should be documented with an invoice, the business owner should take steps to obtain it.
Only when certain conditions are met, under which the taxpayer objectively cannot document the purchase of goods or services with an invoice, can the expense be booked on the basis of other accounting evidence, including a bank payment confirmation.
Additional evidence and supporting documentation
Where using a bank payment confirmation as an accounting document is justified, it is essential to gather additional evidence and supporting documentation. A single transfer confirmation may not contain all the information needed to document the business transaction properly.
Under the principle in the Tax Ordinance Act (Ordynacja podatkowa) (Article 180 § 1), anything that can help clarify the case may be evidence. This means that the business owner can use a variety of documents and materials that together allow the transaction to be documented reliably.
Examples of additional evidence include:
- Email correspondence with the business partner
- Printouts of web pages documenting the purchase
- Contracts or agreements with the other party
- Delivery or receipt documents for the goods
- Other documents confirming that the transaction actually took place
A confirmation of payment by bank transfer can be accounting evidence provided that the taxpayer also has supporting evidence showing that the expense is connected with the business. A single document may not be enough to document the transaction fully
It is also essential that the evidence gathered, taken together, shows that the expense is connected with the business. Under the PIT Act (personal income tax), a tax-deductible cost can be any expense incurred by the taxpayer that is connected with the business.
Practical examples
To better understand the rules for using bank payment confirmations as accounting documents, it is worth analysing specific situations that may arise in business practice. Each situation requires an individual assessment of whether the bank confirmation can be used.
A business owner running a trading business bought goods from a regular supplier. He paid for the goods by bank transfer, but despite a considerable amount of time passing he did not receive an invoice from the seller. He contacted the supplier several times asking for the invoice, but received no reply. In this situation the business owner may consider using the payment confirmation together with documentation of the steps taken to obtain the invoice.
In the first case, where the business owner bought goods from a supplier, paid by bank transfer, but did not receive an invoice and did not request one, booking the expense solely on the basis of the payment confirmation will not be possible. What decides here is the invoice as the proper document in transactions between businesses.
The absence of an invoice where the taxpayer has taken no steps to obtain it means the expense cannot be booked in the KPiR on the basis of a printout of the transfer confirmation from the online bank account.
Special situations and exceptions
There are, however, situations in which using a bank payment confirmation as an accounting document may be justified. This applies above all to cases where it is objectively impossible to obtain an invoice or another standard accounting document.
An example is buying goods from a private individual who does not run a business and is not obliged to issue invoices. In this case, the business owner can use the confirmation of payment by bank transfer, but should make sure to gather additional evidence confirming that the transaction took place.
When buying from private individuals, or where it is objectively impossible to obtain an invoice, the business owner can use a bank payment confirmation. However, additional evidence must be gathered to confirm that the expense is connected with the business
Additional evidence in such situations may include:
- Email correspondence with the seller
- Printouts of online auctions or listings
- Documents confirming receipt of the goods
- Descriptions prepared by the taxpayer
- Other materials documenting the transaction
All the evidence gathered in this way may provide grounds for booking the expense on the basis of the bank transfer confirmation. The key, however, is that the documentation as a whole allows the transaction to be documented reliably and shows its connection with the business.
Technical and formal requirements
Bank payment confirmations used as accounting documents must meet certain technical and formal requirements. Modern banking systems generate many types of transaction confirmations, but not all of them can be used as accounting documents.
The basic requirement is that the confirmation contains all the information needed to document the business transaction properly. The document must be legible, durable and contain all the elements required by the KPiR regulation.
| Document element | Requirements | Example in the confirmation | Notes |
|---|---|---|---|
| Issuer details | Full name of the bank | Bank Przykładowy S.A. | Must be unambiguous |
| Transaction date | Date of issue and transaction date | 2026-01-15 10:30:25 | Time is not required |
| Transaction amount | Value in PLN | PLN 1,500.00 | Clearly stated |
| Recipient details | Name and account number | Jan Kowalski, 12 3456... | Full details |
In practice, it is best if the confirmation is generated directly by the banking system and contains all the data identifying the transaction. Informal or incomplete documents cannot be the basis for accounting entries.
Bank payment confirmations should come directly from the banking system and contain all the data identifying the transaction. Informal documents, handwritten notes or incomplete printouts cannot be the basis for entries in the KPiR
In addition, the confirmation must be stored in a way that keeps it durable and legible for the entire period required by law. This applies to documents in both paper and electronic form.
Archiving and storing documents
Bank payment confirmations used as accounting documents are subject to the same archiving and storage rules as other accounting evidence. The business owner must ensure that these documents are properly stored for the period required by law.
The basic archiving rules include:
- Protecting documents against destruction or loss
- Keeping documents legible throughout the storage period
- Being able to find documents quickly in the event of an audit
- Properly labelling and sorting documents
- Protecting documents against unauthorised access
For electronic documents, such as payment confirmations downloaded from the banking system, appropriate backups and technical safeguards are needed. Loss of electronic data may make it impossible to prove the costs incurred during a tax audit.
Consequences of incorrect documentation
Using bank payment confirmations incorrectly as accounting documents can have serious tax consequences. The tax authorities may question whether business transactions were documented correctly and refuse to recognise the costs incurred.
The main risks of incorrect documentation include:
- The tax authorities refusing to recognise tax-deductible costs
- Having to pay the tax shortfall with interest
- Possible tax penalties
- Longer and more complicated tax audits
- Difficulty proving the actual nature of the transaction
Incorrect documentation of business transactions may lead the tax authorities to refuse to recognise tax-deductible costs. The business owner should always aim to obtain the proper accounting documents and treat bank payment confirmations as a last resort in justified cases
It is particularly important that the business owner can show that they took all reasonable steps to obtain the proper accounting document. Failure to take such steps may be interpreted as an attempt to circumvent the rules on documenting business transactions.
