In the Polish economic system, an invoice is much more than just a document confirming a sale. It is a fundamental element of commerce, serving as the primary tool for verifying transactions, the backbone of the Value Added Tax (VAT) system, and a key instrument for ensuring the financial liquidity of businesses. Correct invoicing is not only a legal obligation but also a sign of professionalism and a prerequisite for the smooth operation of a company. Errors in this area can lead to serious tax consequences, disputes with contractors, and cash flow problems.
In the coming years, Polish entrepreneurs will face a historic transformation in the field of invoicing. This refers to the National System of e-Invoices (Krajowy System e-Faktur - KSeF), which will evolve from a voluntary tool into a mandatory, central platform for exchanging invoices. This digital revolution will irreversibly change the rules of the game, automating and standardizing processes that for decades have relied on paper documents and their electronic PDF counterparts. Understanding these upcoming changes is crucial today to ensure legal compliance and maintain a competitive edge in the market.
This guide has been created to comprehensively and accessibly walk entrepreneurs through all aspects of invoicing in Poland. Starting with the fundamental question of who must issue an invoice and when, through a detailed analysis of the mandatory elements of the document, to a deep dive into the world of electronic invoices and the KSeF revolution. It will also cover the rules for document storage, procedures for correcting errors, and an overview of modern online tools that can automate and simplify the entire process. After reading this article, every entrepreneur will be fully prepared for the current and future challenges related to issuing invoices.
Who Must Issue an Invoice and When?
Understanding the obligation to issue invoices is fundamental to running a business. As a rule, this obligation rests with entities registered as active VAT payers for every transaction with another business (B2B).
Entrepreneurs who are exempt from VAT (due to an annual turnover limit of PLN 200,000 or the nature of their business activities) do not have to issue invoices automatically. However, this obligation arises if the buyer—whether a company or a consumer—requests one within 3 months of the transaction. For sales to individuals (consumers), a receipt is the standard document, and an invoice is issued only upon their request.
Timing is also key. According to the general rule, an invoice must be issued no later than the 15th day of the month following the month in which the sale was made. At the same time, it cannot be issued earlier than 60 days before the transaction to avoid the risk of it being considered a so-called "empty invoice" (an invoice for a transaction that has not yet occurred).
The Anatomy of an Invoice - What Must the Document Contain?
For an invoice to be valid, it must contain a strictly defined set of information. A full VAT invoice, in accordance with Art. 106e of the VAT Act, must include, among other things: the issue date, a sequential number, the seller's and buyer's details along with their NIP (Tax Identification Number), the date of sale, the name of the goods/service, quantity, net unit price, the VAT rate and amount, and the total amount due.
An invoice issued by a taxpayer exempt from VAT has a simplified form—it does not include information about the tax rate and amount. However, it is important to remember the need to indicate the legal basis for the exemption if it results from the type of activity conducted (a subject-based exemption). For low-value transactions (up to PLN 450), a simplified invoice is sufficient; this role is often fulfilled by a fiscal receipt that includes the buyer's NIP number.
Want to be sure your invoices contain all the required elements? Read our detailed guide.
The Digital Revolution - Electronic Invoices and KSeF
An electronic invoice (e.g., in PDF format) is a standard today, fully equivalent to its paper version. Its use, however, requires the recipient's consent and ensuring the document's authenticity, integrity, and legibility.
The real revolution will come with the National System of e-Invoices (KSeF). This is a central, government platform that will become mandatory for most entrepreneurs starting from 2026. All B2B invoices will have to be issued in a structured XML format and sent through KSeF. The date the invoice is sent to the system will also be its date of issue and receipt by the buyer, which will fundamentally change the document workflow in companies.
Storing Invoices - How Long and in What Form?
Tax regulations clearly define archiving obligations. Invoices must be stored for 5 years, counting from the end of the calendar year in which the tax payment deadline passed. This means that documents from 2019 can only be safely destroyed in January 2026.
The law provides great flexibility regarding the storage format—it can be either paper or electronic. Importantly, you can legally scan paper invoices and then destroy their physical originals, provided the scans are legible and their integrity is guaranteed. After the implementation of KSeF, the state will take over the archiving obligation for structured invoices—they will be stored in the system for 10 years.
Wondering how to optimize your company's archive? Read more about: The Rules and Deadlines for Storing Accounting Documents.
When an Error Occurs - Correcting and Canceling Invoices
Everyone makes mistakes on invoices. The law provides clear paths to fix them. The primary tool is a correcting invoice (faktura korygująca), issued by the seller to amend substantive errors (e.g., in price, quantity, VAT rate) or formal ones.
In the case of minor formal errors (e.g., a typo in the address, the wrong NIP), the buyer can issue a correcting note (nota korygująca), which, however, requires the seller's acceptance. It is important to remember that with the advent of mandatory KSeF, correcting notes will be eliminated, and the only way to fix errors will be through a correcting invoice. Canceling an invoice is possible only in an exceptional situation: when the transaction did not actually happen, and the document was not delivered to the buyer.
Want to know how to fix an error on an invoice step-by-step? See our article.
Which Invoicing Tool Should You Choose?
In the age of digitization and KSeF, good online invoicing software is a necessity. When choosing software, the key criterion is its full and proven integration with KSeF. It is also worth paying attention to additional features, such as inventory management, online payments, recurring invoicing, or the availability of a mobile app.
There are many proven providers on the Polish market, such as Fakturownia, iFirma, inFakt, or wFirma, who offer packages tailored to the needs of both freelancers and larger companies. Choosing the right tool will allow you to automate your work and ensure compliance with dynamically changing regulations.
Looking for the perfect program for your company? Read more on generating invoices online with PaveNow.
Summary
Proper invoicing is the lifeblood of any business activity. From understanding basic obligations, through knowing deadlines and required elements, to adapting to the KSeF digital revolution—each of these aspects has a direct impact on legal compliance, financial liquidity, and the operational efficiency of a company.
The Golden Rules of Invoicing - A Checklist
- Identify your obligation - Are you an active VAT payer or an exempt entity? Remember that even as a "non-VAT payer," you must issue an invoice upon request.
- Keep track of deadlines - The standard is the 15th of the following month, but remember the exceptions for your industry and do not issue invoices earlier than 60 days before the transaction.
- Ensure data completeness - Use a checklist of mandatory elements, paying special attention to the differences between a VAT invoice and an invoice from an exempt entity.
- Prepare for KSeF - Check if your invoicing software is ready for mandatory integration from 2026. This is the most important criterion for choosing a tool for the coming years.
- Archive wisely - Store invoices for 5 years from the end of the year in which the tax payment deadline passed. Consider digitizing your archive—scanning paper invoices is legal and efficient.
- Correct properly - Remember that quantitative and substantive errors are corrected by the seller (correcting invoice), while formal errors are corrected by the buyer (correcting note). After KSeF implementation, the correcting note will disappear from use.
- Choose the right tool - Invest in online invoicing software that will automate your work and ensure compliance with regulations.
