Business owners who keep a KPiR (tax revenue and expense ledger) sometimes have to reduce a tax-deductible cost they have already booked, because the payment for it was made in a way that breaks the rules. Most often this means paying cash for a transaction with another business worth more than PLN 15,000, or transferring money to a bank account that is not on the VAT taxpayer white list. In such cases a special cost correction procedure applies, and it requires a proper accounting document. The cost correction document (dowód korekty kosztu) is the key element of this procedure and must meet specific legal requirements.
The obligation to make these corrections comes from Article 22p of the PIT Act (personal income tax), and the data the document must contain comes from § 6 section 3 point 2 of the regulation on keeping the tax revenue and expense ledger (Journal of Laws (Dz.U.) 2025 item 1299, applied from 1 January 2026). The former obligation to correct costs merely because an invoice was not paid on time (Article 24d of the PIT Act) was repealed on 1 January 2016. Today, if a liability is not paid within 90 days of the due date, income is increased when calculating the advance payment and in the annual return (Article 44 section 17 point 2 and Article 26i section 1 point 2 of the PIT Act) - the costs in the KPiR are not corrected.
A business owner who booked an expense as a cost but paid for it in breach of Article 22p of the PIT Act reduces tax-deductible costs in the month in which that payment was made. Every entry in the ledger must be based on a proper document recording the business event
The cost correction procedure is not optional - it is a legal obligation under tax law. Failing to follow it can lead to tax arrears with late-payment interest and, in more serious cases, to liability under the Fiscal Penal Code. That is why every business owner keeping a tax revenue and expense ledger should know exactly how to prepare cost correction documents.
Mandatory elements of a cost correction document
A cost correction document cannot be drawn up in any way you like - its content is set out in the regulation on keeping the tax revenue and expense ledger. Each such document must contain all the elements required by law so that it can serve as the basis for ledger entries.
Under § 6 section 3 point 2 of the KPiR regulation, documents showing a reduction of tax-deductible costs or an increase of revenue under Article 22p of the PIT Act must contain at least specific data. These requirements are not a mere formality - meeting them is a condition for the document to count as a proper accounting record. When a bank payment confirmation can serve as a ledger record is explained separately.
The KPiR regulation in § 6 section 3 point 2 sets out what data a cost correction document must contain. Every element is mandatory, and leaving one out may undermine the value of the document and cause problems during a tax audit
Data required in a correction document
Every cost correction document must contain the following elements:
- Date of issue and month of correction - the document must show a clearly stated date on which it was drawn up and the month in which tax-deductible costs are reduced or revenue is increased
- Reference to the source document - you must precisely indicate the invoice or bill, and if there was no obligation to issue an invoice, the contract or other document on the basis of which the cost was recognised as a tax-deductible cost
- Correction amount - the document must state exactly the amount by which the taxpayer reduces tax-deductible costs or increases revenue
- Signature of the person who prepared it - the document must be signed by the person responsible for preparing it
The date of issue and the month of correction are two different elements that must be clearly distinguished in the document. The date of issue is when the document was drawn up, while the month of correction is the accounting period in which costs are reduced under Article 22p section 2 of the PIT Act
The reference to the source document must be precise enough to identify unambiguously the invoice, bill or other document the correction concerns. In practice this means giving the document number, its date of issue and the name of the counterparty, and for an invoice issued in KSeF (National e-Invoicing System) - also its KSeF number.
Deadlines for correcting costs
Article 22p section 2 of the PIT Act sets out in which month a business owner must correct costs if a payment was made in breach of the rules. This deadline is binding and missing it can have negative tax consequences.
The moment of correction depends on the type of breach: what counts is the month in which the payment was made without a payment account, the month in which a transfer to an account outside the white list was ordered, or the month of a payment that bypassed the split payment mechanism when the invoice contained the words "mechanizm podzielonej płatności" (split payment mechanism).
The cost correction deadline follows directly from the Act and cannot be extended. Missing it means the tax advance has been understated and can lead to tax arrears with late-payment interest
Payment without a payment account above PLN 15,000
If the other party to the transaction is another business and the one-off value of the transaction exceeds PLN 15,000 (regardless of the number of payments arising from it), payment should be made through a payment account (Article 19 of the Entrepreneurs' Law, Prawo przedsiębiorców). The part of the cost paid otherwise, for example in cash, is not a tax-deductible cost, and if it has already been booked, the business owner reduces costs in the month in which that payment was made.
If costs are insufficient for the reduction, the business owner must increase revenue accordingly (Article 22p section 2 point 2). This mechanism ensures that the correction is made regardless of the level of costs in a given month.
Transfer to an account outside the white list
If a transfer for an invoice from an active VAT payer went to an account that was not in the register of taxpayers on the day the transfer was ordered (the VAT taxpayer white list, Article 96b section 1 of the VAT Act), the business owner reduces costs in the month in which the transfer was ordered - if the transaction exceeds PLN 15,000. This is the rule in 2026; from 1 January 2027 (Act of 18 September 2026, Dz.U. 2026 item 1371) Article 22p section 1 will cover only a payment made without a payment account - the conditions of a transfer to an account outside the white list and of bypassing the split payment mechanism will disappear, and section 4 (including the ZAW-NR notification) will be repealed; payments for invoices issued before that date are governed by the previous rules.
You can avoid a correction for a transfer to an account outside the white list by filing a ZAW-NR notification with the head of the tax office (urząd skarbowy) within 7 days of ordering the transfer (Article 22p section 4 point 1 of the PIT Act). The correction also does not apply, among other things, to payments made with the split payment mechanism (Article 22p section 4 point 3)
This mechanism is meant to limit non-transparent cash settlements and payments to unverified accounts. Thanks to the correction obligation, a tax-deductible cost is available only where payment was made in the way the law requires.
How to prepare a correction document
Preparing a cost correction document requires a set procedure that ensures the document meets the legal requirements and is useful for accounting and tax purposes. The process should be carried out systematically and with due care.
The first step is to identify all payments that require correction in a given period. Review the invoices and bills booked as costs, checking the transaction value, the method of payment and the account to which the transfer was made.
Payments requiring correction should be identified regularly, ideally at the end of each month. This lets you prepare correction documents on time and avoid missing the statutory deadlines
Steps in preparing the document
- Review of payments for transactions above PLN 15,000 (method of payment, account on the white list)
- Identification of the specific invoices and bills requiring correction
- Calculation of the exact amounts to be corrected
- Preparation of the correction document with all the required data
- Entry in the ledger based on the document prepared
When preparing the document, pay particular attention to the accuracy of all data, especially amounts and dates. Errors in these elements can lead to irregularities in the tax revenue and expense ledger and to problems during tax audits.
Practical aspects of booking corrections
In accounting practice, cost corrections can be booked in different ways, depending on the method adopted by the business owner and the specific situation. What matters most is keeping the entries transparent and logical.
A cost correction can be booked on the last day of the month on the basis of a summary of cost corrections for that period. A reduction of costs is entered in the ledger with a minus sign (-) or in red (§ 6 section 5 of the regulation). This approach keeps the tax revenue and expense ledger systematic and orderly, and makes it easier to check that corrections are made on time. We keep day-to-day KPiR entries for our clients, including correction summaries, as part of our accounting services.
Booking corrections on the last day of the month on the basis of a summary is a solution often used in practice. It keeps entries transparent and makes financial analysis easier
Summary of cost corrections
A summary of cost corrections should include:
- A list of all corrected documents with full identification data
- The amounts originally booked as costs
- The correction amounts, split into cost reductions and revenue increases
- The legal basis for the corrections made
- The dates on which the individual correction documents were prepared
Such a summary is not only the basis for booking but also a valuable control tool, allowing you to track all corrections made and their effect on the business's financial result.
Consequences of breaking the rules
Breaking the rules on correcting costs can have serious consequences for a business owner. Overstated costs mean understated advance payments and tax, and the tax authorities may check how payments were made during audits.
The basic consequence is the need to correct the tax return for the year in which tax-deductible costs were shown incorrectly, and to pay the additional tax. This can give rise to tax arrears together with late-payment interest.
Stating untrue information in a tax return can lead to liability under the Fiscal Penal Code (Article 56 of the Kodeks karny skarbowy, KKS). As a rule, a legally effective correction of the return, together with prompt payment of the arrears, removes liability, provided preparatory proceedings have not been opened earlier (Article 16a KKS)
Types of sanctions
A business owner may face the following consequences:
- Payment of additional tax for the periods affected by irregularities
- Late-payment interest calculated from the day the arrears arose
- Liability under the Fiscal Penal Code (a fine)
- Additional audits and checks by the tax authorities
- Problems with accounting credibility in the future
It is worth stressing that the consequences can be long-term and affect the business owner's relations with the tax authorities for a long time. That is why complying with the cost correction rules is not only a legal obligation but also an investment in the stability and credibility of the business.
Cost correction document template
To prepare a cost correction document in practice, you need to include all the elements required by law. Below is a sample structure of such a document, which business owners can use as an illustrative template (the law does not set an official template - it only sets the minimum scope of data).
| Document element | Sample content | Legal notes |
|---|---|---|
| Document title | Cost correction document No. 001/2026 | Numbering for record-keeping |
| Date of issue | 31 March 2026 | Date the document was drawn up (§ 6 section 3 point 2 letter a) |
| Month of correction | March 2026 | Month of the payment made in breach of Article 22p |
| Source document | Invoice No. 123/2026 of 2 March 2026 (KSeF number), transaction PLN 18,000, of which PLN 2,500 was paid in cash on 5 March 2026 | Full identification of the document (letter b) |
| Basis of correction | Article 22p section 1 point 1 and section 2 of the PIT Act | Supporting element, makes audits easier |
| Correction amount | PLN 2,500.00 | Amount of the cost reduction (letter c) |
| Signature | Jan Kowalski - accountant | Person who prepared the document (letter d) |
The correction document template can be adapted to the needs of a given business, but all the elements required by the regulation must be kept. You can add supporting elements, but you must not leave out any of the mandatory ones
The document can be prepared on paper or electronically, provided its integrity and verifiability are ensured. In electronic form, protection against unauthorised changes is particularly important.
Special situations in cost corrections
In business practice, special situations may arise that require an individual approach to cost corrections. Such cases often raise doubts among business owners and require a careful analysis of the law.
One such situation is paying an invoice partly by transfer and partly in cash. In that case only the part of the cost for which the payment was made in breach of Article 22p (for example in cash) is corrected, which requires a precise calculation of the correction amount and proper documentation of the partial payments.
With partial payments of an invoice, only the part of the cost corresponding to the payment made in breach of the rules is corrected. This requires detailed records of payments and a precise calculation of the correction amounts for each document separately. These rules apply accordingly to fixed assets and to intangible assets (Article 22p section 3 point 1)
Another problematic situation is invoices issued in foreign currencies. In such cases the correction should be made at the exchange rate applied on the day the cost was originally booked, which may require additional calculations and exchange-rate documentation.
Corrective invoice versus a cost correction document
The document under § 6 section 3 point 2 of the regulation is not prepared when a cost changes because of a corrective invoice (for example a discount or a return of goods). Such a correction is recognised in the period in which the corrective invoice was received or - if there is none - another document confirming the reason for the correction; if the correction results from an arithmetic error or another obvious mistake, the original period is corrected (Article 22 sections 7c-7d of the PIT Act). A corrective invoice in KSeF contains the KSeF number of the invoice being corrected (Article 106j section 2 point 2a of the VAT Act), and the corrective note under Article 106k of the VAT Act no longer exists from 1 February 2026.
Practical example: In March 2026 a service company booked an invoice from another business for renovation services worth PLN 18,000 net. In April 2026 it paid the whole amount in cash. Because the transaction value exceeds PLN 15,000 and the payment was made without a payment account, in April 2026 the company had to prepare a cost correction document and reduce its costs by PLN 18,000, and if its costs in that month had not been sufficient - increase its revenue by the missing amount.
Documenting correction processes
Properly documenting cost corrections is key to keeping your accounts in order and preparing for possible tax audits. The documentation system should be comprehensive and make it easy to trace all operations carried out.
The core of the documentation system is a register of cost corrections, in which all correction documents are recorded together with their basic data. The register should be kept chronologically and contain references to the corresponding entries in the tax revenue and expense ledger. When a WZ goods issue note goes into the ledger is covered in a separate guide.
The register of cost corrections is a key control tool and should be kept systematically throughout the tax year. Without it, a tax audit may be more difficult and the risk of accounting errors increases
It is also worth regularly analysing the effects of corrections made, which helps you understand their impact on the business's financial result and improve cash-flow management.
