Keeping accounts is not only about entering records correctly in the books, but also about storing accounting documents properly. Every entrepreneur in Poland must archive records in line with the law. Improper storage may have serious financial and legal consequences.
Proper archiving of accounting documents requires knowledge of the rules on retention periods, storage methods and the types of documents that can support accounting entries. Modern technology makes it possible to keep records electronically, which greatly simplifies archiving but comes with additional data security requirements.
Types of accounting documents in the KPiR
The KPiR (tax revenue and expense ledger) is the basis of tax settlement for many entrepreneurs. The rules clearly set out which documents can support entries in this ledger. From 1 January 2026, the acceptable accounting documents are defined by the Regulation of the Minister of Finance and Economy of 6 September 2025 on keeping the tax revenue and expense ledger (Journal of Laws (Dz.U.) 2025 item 1299), which replaced the Regulation of the Minister of Finance of 23 December 2019. Whether a bank payment confirmation alone is enough for the KPiR is something we look at in a separate article.
Only documents specified in the KPiR regulation can support entries in the tax revenue and expense ledger (§ 6 section 3). Using incorrect accounting documents may lead the tax authorities to treat the ledger as defective or unreliable
The main categories of accounting documents are invoices, VAT RR invoices (issued for purchases from flat-rate farmers), bills and customs documents issued in line with separate regulations. All of these documents must meet certain formal requirements to be treated as valid accounting documents. Each of them also has to be marked properly — how to assign the numbers is shown in our guide to numbering accounting documents in the KPiR.
The second category consists of documents recording a reduction of tax-deductible costs or an increase in revenue under Article 22p of the PIT Act. These documents must show the date of issue and the month in which the change is made, the invoice or contract on which the cost is based, the amount of the adjustment and the signature of the person preparing the document.
Accounting documents must contain all elements required by law. If any required element is missing, the document may not be accepted as an accounting document
The third category consists of other documents listed in paragraphs 7 and 8 of the regulation, which must confirm that a business transaction took place in line with its actual course. These documents require a reliable identification of the issuer, the dates of the business transaction, the subject of the transaction with its value and the signatures of persons authorised to document the transaction.
Detailed requirements for accounting documents
The rules set out precise requirements for the content of accounting documents. Each document must reliably identify the issuer or the parties to the business transaction, including their names and addresses. The date of issue and the date of the business transaction must be clearly stated, and if the dates are the same, one date is enough.
The subject of the business transaction must be described accurately, with its value and quantity, where the subject can be measured in physical units. The signatures of persons authorised to document the transaction are also required, and the document itself must be numbered or marked in another way that links it to the accounting entries
The regulation also treats as accounting documents accounting notes used to correct entries, proof of postal and bank charges and other proof of payments, including those made using payment booklets (§ 7). Internal documents may be prepared only in the cases listed in § 8, e.g. for per diems for business trips or the part of utility bills attributable to the business. The 2026 regulation no longer provides for daily summaries of documents or transfer documents.
In practice, this means that not every document can be treated as an accounting document. A bank statement on its own, as a rule, does not meet the requirements of an accounting document for a purchase, because it does not specify the subject of the business transaction, its value or quantity. It also lacks the signatures of persons authorised to document the transaction. Bank charges and fees themselves, however, are documented by it (§ 7 point 2).
A sale and purchase contract may be the basis for recording an expense in the tax revenue and expense ledger, but it does not give the right to deduct VAT. Goods bought under such a contract are recorded in column 12 of the KPiR for purchases of goods for resale and materials (from 2026; previously column 10)
Understanding these rules correctly is key to keeping the books properly. Entrepreneurs must remember that only documents meeting all legal requirements can support entries in the tax revenue and expense ledger. The WZ note, for instance, often raises doubts — a separate post explains how to record a WZ goods issue note in the KPiR.
Rules for keeping the tax revenue and expense ledger
The tax revenue and expense ledger is opened on 1 January of each tax year or on the date the business starts during the year (§ 19 of the regulation). The first entry in a ledger opened during the year is the physical stocktake (opening inventory) of goods for resale, materials, semi-finished products, work in progress, finished products, rejects and waste on the date the business starts (§ 20 section 1).
The ledger may be kept on paper or electronically, but the PIT Act introduces an obligation to keep it using computer software and to send it to the tax office (urząd skarbowy) after the end of the year, by the deadline for filing the annual return (Article 24a section 1e). This obligation applies to taxpayers who file JPK_V7 (VAT return with records, SAF-T file) from 2026 and to all others from 2027 (Article 66 section 1 of the Act of 29 October 2021, Dz.U. 2021 item 2105, as amended by Dz.U. 2023 item 1059). If the ledger is kept on paper, it must be bound and its pages numbered consecutively (§ 5 of the regulation).
Keeping the ledger electronically requires storing the data in a way that protects it against destruction or corruption. The software must be able to export the ledger in the JPK logical structure, which the tax authority may request (Article 193a of the Tax Ordinance Act (Ordynacja podatkowa))
Reliability is fundamental to the legal value of the ledger. The ledger must be kept in line with the regulation, using the prescribed template and the explanatory notes to the template (§ 4 section 2). Particular attention should be paid to recording incidental costs of purchasing goods for resale and materials in the correct column.
Recording rules differ depending on the type of transaction. Incidental costs of purchasing goods for resale are recorded in column 13 of the KPiR (from 2026; previously column 11), not in the column for other expenses. If materials or goods arrive before the invoice, a detailed description of the delivery is prepared and the entry is made on that basis; the description is then attached to the invoice or supplemented with the invoice number, including the KSeF (National e-Invoicing System) number (§ 9 section 1). KPiR entries, including those based on a delivery description, are part of the bookkeeping services we provide to clients.
As a rule, an entrepreneur is not obliged to record all cost invoices, except those for purchases of goods for resale and materials. These invoices must be recorded, because the exception in § 4 section 4 point 3 of the regulation does not cover omitting them, and omitting them may lead to the ledger being treated as unreliable
Keeping the ledger unreliably is, as a rule, a fiscal offence (in less serious cases a fiscal petty offence), while keeping it defectively is a fiscal petty offence (Article 61 of the Fiscal Penal Code). The ledger is unreliable if it records an event that did not happen, shows amounts other than the actual ones or omits an event that actually took place.
Procedure for archiving accounting documents
Proper archiving of accounting documents requires a systematic approach and set procedures. The archiving process starts when the document is received and continues throughout its retention period.
- Checking received documents for completeness and formal correctness
- Entering documents into the accounting system with an appropriate description and number
- Sorting documents according to the adopted organisational system
- Placing documents in suitable files or archive boxes
- Labelling files according to the adopted classification system
- Preparing a list of documents transferred to the archive
- Placing documents in a secure storage location
- Keeping a register of documents held in the archive
Paper documents need special protection against moisture, sunlight and high temperatures. It is worth copying or scanning thermal receipts, because they fade quickly and may become illegible after a few years
Documents should be sorted chronologically, with numbering consistent with the numbering used in the tax revenue and expense ledger. If there is a large volume of documents, monthly or quarterly files are recommended, which makes it easier to find specific documents later.
Electronic archiving requires additional security measures. Electronic documents must be copied regularly to independent data media, and the storage system should be protected against unauthorised access and accidental data loss.
Requirements for the storage location
The law sets out requirements for where accounting documents are stored. The tax revenue and expense ledger and accounting documents should be kept at the place where the business is carried out or at the place indicated as the registered office or branch, and where bookkeeping is outsourced to an accounting office – at the place specified in the contract with the office. Failing to keep the ledger at the proper place is a fiscal offence punishable by a fine of up to 240 daily rates, and in less serious cases a fiscal petty offence (Article 60 § 2 and § 4 of the Fiscal Penal Code).
| Document type | Storage location | Additional requirements | Retention period |
|---|---|---|---|
| Paper KPiR | Registered office or place of business | Protection against destruction | Until time-barred, as a rule 5 years |
| Electronic KPiR | Registered office or place of business | Data security | Until time-barred, as a rule 5 years |
| Accounting documents | Registered office or place of business | Chronological order | Until time-barred, as a rule 5 years |
| Accounting office records | Place specified in the contract with the office | Notification in the CEIDG application | Until time-barred, as a rule 5 years |
If you use an accounting office, the ledger and accounting documents may be kept at the place specified in the contract with the office. The details of the person keeping the accounting records and the address where they are stored are given in the identification notification – an entrepreneur registered in CEIDG (Central Register and Information on Economic Activity) does so in the CEIDG application and reports changes in an update notification (Article 5 sections 4 and 5a and Article 9 section 1 of the Act on the Registration and Identification of Taxpayers and Payers)
The storage location must provide suitable conditions for long-term storage of documents. The room should be dry, protected against unauthorised access and equipped with suitable fire protection.
Electronic documents require additional technical safeguards. The storage system should include regular backups, antivirus protection and user access control. Keeping an access log for electronic documents is also recommended.
Retention periods for documents
The basic retention period for the tax revenue and expense ledger and accounting documents is 5 years, counted from the end of the calendar year in which the deadline for paying the income tax settled on the basis of the ledger passed – the books and documents are kept until the tax liability becomes time-barred (Article 86 § 1 and Article 70 § 1 of the Tax Ordinance Act). This period cannot be shortened, and it may be extended if the limitation period is suspended or interrupted (Article 70 § 2–8).
The retention period for accounting documents ends when the tax liability becomes time-barred, i.e. as a rule 5 years from the end of the year in which the tax payment deadline passed. Destroying documents too early may have serious legal consequences
In practice, this means that documents for 2020 (return and tax payment due by 30 April 2021) can be destroyed only after 31 December 2026. Entrepreneurs must keep an accurate record of the retention periods for each year's documents. Businesses keeping full accounting books also apply the periods in Article 74 of the Accounting Act – e.g. books and vouchers for at least 5 years from the beginning of the year following the financial year to which they relate.
Some documents may need to be kept longer under other regulations. Documents relating to fixed assets, long-term contracts or disputes should be kept until the matter is finally resolved.
Purchase documents for fixed assets affect your tax settlement throughout the depreciation period, so in practice they are kept for the whole period of use and then until the tax liability for the year in which they last affected the tax becomes time-barred, e.g. the year of the last depreciation write-off or the sale. This also applies to lease documents and long-term rental agreements
Keeping a calendar of archiving deadlines is recommended, as it helps manage records systematically. Each year's documents should be marked with the earliest possible destruction date.
Consequences of improper storage
Improper storage of accounting documents may have serious legal and financial consequences. The entrepreneur is fully responsible for archiving accounting records in line with the law.
- Fines for failing to keep or for defectively keeping accounting records
- Additional tax liabilities because costs cannot be documented
- Risk of the VAT deduction being challenged for damaged or destroyed invoices
- Problems during tax inspections and difficulty proving that settlements were correct
- Criminal liability for fiscal offences in serious cases
Failing to meet archiving obligations may lead to liability under the Fiscal Penal Code, e.g. failing to keep invoices or proof of purchase is punishable by a fine of up to 180 daily rates (Article 62 § 3 of the Fiscal Penal Code). The tax authorities may also assess a higher tax liability if costs cannot be documented
The loss of documents confirming costs incurred is particularly painful. If there are no proper accounting documents, the tax authority may refuse to recognise costs as tax-deductible costs, which increases the tax base.
Tax inspections focus on checking that accounting records are kept correctly. Being unable to present the required documents, or presenting incomplete ones, may be grounds for treating the ledger as defective or unreliable.
A manufacturing company had been operating for 15 years, systematically archiving its accounting documents. During a tax inspection of settlements from 3 years earlier, all required documents were presented to the inspectors without delay. Thanks to proper archiving, the inspection ended without objections and the company avoided additional tax liabilities and penalties.
Modern methods of electronic archiving
Digital technology makes electronic archiving of accounting documents more and more widely used. Storing documents electronically offers many benefits but requires meeting additional legal and technical requirements.
Electronic archiving requires suitable security systems. Documents must be stored in formats that ensure long-term legibility and data integrity. Using PDF/A or other archiving standards is recommended. Structured invoices issued in KSeF are stored by the system for 10 years from the end of the year of issue, and during that time the taxpayer does not have to store them separately (Article 112aa of the VAT Act).
An electronic archiving system must ensure full integrity of documents throughout the retention period. All changes to documents must be logged and controlled by the security system
Backups are a key element of electronic archiving. Documents should be copied regularly to independent data media kept in different locations. The 3-2-1 rule is recommended: three copies of the data, on two different types of media, with one copy kept outside the company's premises.
Access control for electronic documents requires appropriate security procedures. Each system user should have an individual account with defined permissions. All operations on documents must be recorded in the system log.
Migrating electronic documents to new systems or formats must preserve full data integrity. You should regularly test whether archived documents can still be read
Outsourcing electronic archiving to specialist companies can be a cost-effective solution, especially for small businesses. When choosing an archiving provider, look at security certifications, industry experience and the data availability terms set out in the contract.
