How Long Should You Keep Invoices?

For many entrepreneurs, invoices are everyday, operational documents—proof of purchase, basis for payments, and elements of bookkeeping. In reality, their role is much deeper. They form the legal and financial backbone of a company, a record of its economic history, and crucial evidence in relations with business partners and state authorities. Therefore, proper invoice archiving is not a bureaucratic whim but a fundamental element of risk management. It is a shield that protects a company from severe financial and legal sanctions, as well as the basis for effectively defending its rights during a tax audit. Neglecting the archiving obligation, misinterpreting it, or prematurely destroying documentation is a direct path to serious problems. It can lead to tax settlements being challenged, the loss of the right to deduct VAT, and consequently, the imposition of hefty fines and interest. This article comprehensively demystifies the regulations concerning invoice storage.

How long should accounting documents be kept?

The commonly known "5-year" rule is one of the most misleading simplifications in Polish tax law. Although the number is correct, understanding from which moment to start counting is crucial. In reality, the invoice retention period is inextricably linked to the statute of limitations for tax liability—a dynamic concept that can be significantly extended under certain circumstances.

Legal Basis for Document Storage

The legal basis defining the retention period for tax documentation is Art. 70 § 1 of the Act of August 29, 1997 - the Tax Ordinance. According to this provision, a tax liability expires after 5 years, counting from the end of the calendar year in which the tax payment deadline passed. It is this regulation that forms the foundation for the archiving obligation.

It is crucial to understand that the starting point for calculating the five-year period is not the invoice issue date or the transaction date. It is the end of the calendar year in which the statutory deadline for paying the tax (e.g., VAT, PIT, CIT) resulting from that invoice passed. This nuance is fundamental for correctly determining the archiving period.

This principle is directly confirmed in industry-specific regulations. Art. 112 of the Act on Goods and Services Tax (VAT Act) explicitly states that taxpayers are obliged to store records and all documents related to tax settlement, particularly invoices, until the expiry of the statute of limitations for the tax liability. In this way, the regulations create a coherent and logical system.

Financial Documentation Retention Period - An Example

A consequence of this method of calculation is that, in practice, the document retention period is almost always longer than exactly 5 years. Depending on the type of tax and the moment of the transaction, it can be almost 6, or even close to 7 years. Let's consider the following scenario:

An entrepreneur receives a cost invoice in January 2024. This invoice documents an expense that affects the VAT settlement.

1. VAT for January 2024 is payable by February 25, 2024. The tax payment deadline, therefore, falls within the year 2024.
2. According to Art. 70 § 1 of the Tax Ordinance, the five-year limitation period (and thus the retention period) is calculated from the end of the calendar year in which the payment deadline passed, i.e., from the end of 2024.
3. The retention period, therefore, runs through the full years: 2025, 2026, 2027, 2028, and 2029.
4. This means the invoice from January 2024 must be securely stored until December 31, 2029. Thus, almost 6 years pass from the moment of the transaction.

The situation becomes even more complicated for annually settled taxes, like corporate income tax (CIT). If an invoice concerns a cost included in the annual settlement for 2024, the CIT payment deadline for that year is typically March 31, 2025. In this case, the five-year period is calculated from the end of 2025, meaning the document retention obligation lasts until December 31, 2030—almost 7 years from the transaction date. Understanding this mechanism is crucial to avoid the mistake of prematurely destroying documents.

When Does the Obligation to Store Financial Documentation Extend?

The expiration of a tax liability is not a process that always proceeds passively and uninterrupted. The legislator has provided for a number of circumstances in which the running of the five-year period may be suspended or completely reset (interrupted). In such situations, the obligation to archive documents is automatically extended.

Suspension of the Statute of Limitations Period

Suspension is a temporary "pause" in the counting of the five-year period. The time during which the period is suspended is not included in the limitation period. After the reason for suspension ceases, the period continues to run (it is not counted anew). The most common reasons for suspension, defined in Art. 70 of the Tax Ordinance, are:

• Initiation of proceedings in a case of a fiscal crime or offense, of which the taxpayer has been notified, if the suspicion of the act is related to the non-performance of that liability. This is a common practice of tax authorities, especially when an audit concerns a period that is about to expire.
• Filing a complaint with an administrative court against a decision of a tax authority.
• Issuing a decision to defer the tax payment deadline or to break it down into installments.

Interruption of the Statute of Limitations Period

Interruption is an event with much more far-reaching consequences. It causes the five-year counter to be "reset," and after the cause of the interruption ceases, the limitation period begins to run anew for a full five years. The main causes of interruption are:

• Application of an enforcement measure of which the taxpayer has been notified (e.g., seizure of salary, bank account, or movable property).
• Declaration of the taxpayer's bankruptcy.

An extremely important conclusion flows from these regulations: the archiving obligation is dynamic and closely linked to the company's current legal and tax situation. An entrepreneur cannot mechanically destroy documents after the standard period has passed. They must be absolutely certain that none of the accounting periods covered by the documentation are subject to a tax audit, fiscal penal proceedings, a court dispute, or enforcement. Otherwise, destroying the documents may be considered obstruction of an audit and lead to serious consequences.

Convergence of Regulations - The Accounting Act vs. The Tax Ordinance

An additional regulatory layer is provided by the Accounting Act of September 29, 1994. Art. 74 of this act also specifies minimum retention periods for documentation, which in many cases is 5 years. This applies, among others, to accounting books, accounting records (including invoices), and approved annual financial statements.

At first glance, these periods seem convergent, but the key difference lies in how they are calculated. The Accounting Act often counts the periods from the beginning of the year following the financial year to which the data sets relate, or from the approval of the financial statement. In practice, for documents like invoices, which are both an accounting record and a key document for tax purposes, the principle of prudence should be applied. This means that documentation should be stored for the longer period resulting from potentially overlapping legal regimes. In this case, the period resulting from the Tax Ordinance is superior and more restrictive, as it is linked to the risk of an audit and the possibility of authorities pursuing liabilities.

In What Form Should You Store Invoices? Paper, Scan, or Cloud?

Modern tax law accommodates the digital transformation of business, giving entrepreneurs significant freedom in choosing their document archiving method. The key principle is that the form (paper or electronic) is secondary. What matters most is that the chosen method guarantees the immutability, authenticity, and full accessibility of the documents throughout the entire legally required period. Electronic archiving is not only fully permissible but, when proper procedures are followed, often proves to be safer and more efficient than traditional paper archives.

Equality of Formats: Freedom of Choice for the Entrepreneur

The foundation of the modern approach to archiving is Art. 112a of the VAT Act, which unequivocally equates the legal status of paper and electronic invoices. This provision gives taxpayers the right to choose how to store invoices, regardless of their original form.

This means that the process of digitization—scanning invoices received in paper form and storing them exclusively in digital format—is fully legal and accepted by tax authorities. After making a proper, legible scan and securing it in an archiving system, the paper original can be destroyed. This is extremely important information for companies looking to reduce the costs and space associated with maintaining physical archives.

Moreover, Polish regulations do not impose an obligation to store invoices in the same form in which they were received. A paper invoice can be scanned, and an electronic invoice (e.g., a PDF file) can be printed and stored in paper form, although the latter scenario is a step backward from an efficiency perspective. The choice belongs to the entrepreneur.

The Three Pillars of Proper Archiving (Not Just Electronic)

Regardless of the chosen form—paper or electronic—Art. 112a of the VAT Act imposes an obligation on the taxpayer to ensure three key features of stored invoices throughout the entire archiving period:

1. Authenticity of Origin This means certainty as to the identity of the supplier of goods or the service provider who issued the invoice. In practice, this is not just about an electronic signature. Authenticity can be ensured through any business controls that create a reliable audit trail. Such a trail allows for the unambiguous linking of an invoice to a specific order, contract, goods receipt protocol, or service performance confirmation.
2. Integrity of Content This is the guarantee that the data contained on the invoice has not been altered in any way since it was issued or received. For paper documents, protection consists of their physical security. In the digital world, integrity is ensured by using non-editable formats (e.g., PDF), IT systems with version control, secure document exchange platforms (EDI), or a qualified electronic signature.
3. Readability The document must be human-readable throughout the entire required storage period. This requirement applies to both the ink fading over time on paper invoices and the risks associated with obsolete digital file formats or data carrier degradation.

Understanding these three pillars leads to a significant conclusion: "electronic storage" is not just a technical act of saving a file to a computer disk. It is a legal status that a digital document acquires through the implementation of appropriate processes. Simply having a JPEG file of an invoice on the desktop, without an organized structure, procedures, and backup, does not meet the statutory requirements. For a digital archive to be legally compliant, the scan must be legible, saved in a durable, non-editable format, placed in a logically organized folder structure, and, crucially, covered by a regular backup system. Therefore, switching to a digital archive is not only a technological decision but, above all, the implementation of a process that gives digital documents full legal and evidentiary power.

Consequences of Not Storing Invoices - What Are the Risks of Negligence?

The absence of an invoice or entire accounting documentation is not a minor administrative oversight. It is an event that triggers a cascade of negative consequences under tax law, fiscal penal law, and for some entities, the Accounting Act. The sanctions are severe, multi-dimensional, and can seriously threaten the financial stability and even the continued operation of a business.

Tax Risk - Loss of Right to Deductions and Costs

The most direct and financially tangible consequence of a missing cost invoice is the loss of the right to reduce one's tax liabilities.

• Loss of the right to deduct VAT According to the fundamental principle expressed in Art. 86(1) of the VAT Act, an invoice is the primary document entitling a taxpayer to deduct input tax. Its absence during an audit is the most common and simplest basis for the tax authority to challenge the deduction. Although the case law of the Court of Justice of the EU allows, in exceptional situations, the possibility of proving the right to a deduction by other means, this is an extremely difficult, lengthy, and high-risk process.
• Challenging of tax-deductible costs A similar situation occurs with income taxes (PIT and CIT). The absence of an invoice or other accounting proof documenting an expense makes it impossible to classify it as a tax-deductible cost. This leads to an artificial inflation of the taxable income.
• The Financial Consequence Both of the above situations lead to the same result—the creation of a tax arrear. The tax authority determines the correct amount of tax, and the entrepreneur is obliged to pay the difference along with accrued default interest.

Fiscal Penal Liability - High Fines and Proceedings

The Fiscal Penal Code (KKS) treats documentation irregularities as separate prohibited acts (fiscal crimes or offenses), regardless of whether an actual depletion of public-law liabilities occurred. This means a penalty can be imposed even if the tax was paid in the correct amount.

• Failure to keep a ledger (Art. 60 KKS) If the documentation deficiencies are so serious that the authority considers the tax ledger (e.g., the Revenue and Expense Ledger) to be de facto not kept or kept in a way that prevents the determination of the tax base, the perpetrator faces a fine of up to 240 daily rates.
• Unreliable keeping of a ledger (Art. 61 KKS) Even if the ledger is kept, but it is missing individual invoices or other entries are inconsistent with reality, this can be classified as unreliable bookkeeping. This offense is also punishable by a fine of up to 240 daily rates.
• Obstruction of an audit (Art. 83 KKS) Knowingly failing to present ledgers or other documents related to the subject of the audit, including invoices, upon the request of the auditing authority is a separate prohibited act. It can be classified as frustrating or obstructing an official act and is subject to a fine for a fiscal offense.

To understand the real scale of the threat, the concept of a "daily rate" must be explained. Its amount is set by a court based on the perpetrator's financial situation and income, within the limits defined by the Fiscal Penal Code, which are linked to the minimum wage. In 2024, the minimum daily rate was over 140 PLN, and the maximum could exceed 56,000 PLN. This means that the maximum fine for a fiscal crime (240 daily rates) could theoretically reach several million PLN, although in practice for small and medium-sized enterprises, these amounts range from a few to several tens of thousands of PLN.

Sanctions from the Accounting Act

For entities obliged to maintain full accounting (e.g., limited liability companies, joint-stock companies), there is an additional plane of responsibility. Art. 77 of the Accounting Act provides for separate criminal sanctions for failing to keep accounting books, keeping them contrary to the provisions of the act, or providing unreliable data in them. Such acts are punishable by a fine or imprisonment for up to 2 years, or both penalties jointly.

Importantly, criminal liability under the Accounting Act does not preclude liability under the Fiscal Penal Code. This means that an entrepreneur or the person responsible for bookkeeping can be punished under both acts. In the case of a concurrence of two fines, the more severe penalty is enforced.

Potential Sanctions for Errors in Invoice Archiving - A Summary

This table clearly proves that the stakes in the game of proper archiving are much higher than just "paying the overdue tax." It is a complex system of interconnected vessels, where one act of negligence can trigger an avalanche of severe and costly legal and financial consequences.

Building a Coherent System - From Issuing an Invoice to Its Archiving

Proper and secure archiving is the last, but extremely important, link in the life cycle of every invoice. The effectiveness of this final stage, however, is inextricably linked to the quality of all previous steps—from the correct issuance of the document, through avoiding common mistakes, to its secure storage. Building a coherent, well-thought-out document management system is the best investment in a company's legal and financial security.

Archiving as the Culmination of the Invoicing Process

It must be remembered that even the best-organized and secured archive will not fix mistakes made at earlier stages. Storing a faulty invoice for years is merely postponing the problem. Therefore, it is crucial to perceive archiving not as an isolated duty, but as the natural culmination of the entire invoicing process.

The foundation of secure archiving is a document that is complete and error-free from the very beginning. So, before an invoice goes into our archive, we must be absolutely certain that we know what a VAT invoice must contain. Every missing element, such as the buyer's NIP (Tax Identification Number), the date, or the correct tax rate, is a potential flashpoint during a future audit.

Business practice shows that certain mistakes on invoices are repeated exceptionally often, leading to unnecessary corrections and disputes. Understanding the most common errors on VAT invoices allows you to eliminate the risk at its source, before a faulty document is booked, paid, and archived for years to come.

Ultimately, the entire process comes down to developing solid, repeatable procedures within the company. Knowing how to correctly issue VAT invoices is the first and most important step toward building a system in which archiving becomes a simple, logical, and secure conclusion to the life cycle of every financial document.

Summary

Managing invoice archiving, although regulated by complex provisions, comes down to a few key principles that every entrepreneur should implement in their company. The following checklist is the essence of the information presented in this article:

• The 5-Year+ Rule: Always count the five-year retention period from the end of the calendar year in which the payment deadline for the tax resulting from the invoice passed, not from its issue date.
• Monitor the Risk: Be aware that an ongoing tax audit, fiscal penal proceedings, a court dispute, or administrative enforcement can suspend or interrupt the statute of limitations, significantly extending the archiving obligation.
• Choose the Form Wisely: Digitize paper documents to save space and increase security, but do it smartly. Ensure the authenticity of origin, integrity of content, and readability of digital copies throughout the entire retention period.
• Backup is Fundamental: Regularly back up your digital archive. Data loss is tantamount to losing documentation and exposes the company to the full legal and tax consequences.
• Order Means Security: Maintain a logical, chronological structure for your archive, divided into accounting periods. This will allow you to instantly find any document upon the request of audit authorities.

In an era of widespread digitization and the upcoming obligation to use the National System of e-Invoices (KSeF), manual archive management is becoming a process that is not only time-consuming but also increasingly risky. Modern invoicing systems, such as PaveNow, not only facilitate the correct and compliant issuance of documents but also largely automate the process of secure archiving. By storing invoices in a secure cloud, they automatically handle backups, ensure constant access to data, and guarantee compliance with the requirements for authenticity, integrity, and readability, taking a significant part of the responsibility off the entrepreneur's shoulders and allowing them to focus on what matters most—running their business.