The National e-Invoice System (KSeF), which introduces the mandatory use of a structured invoices, will come into force on 1 February 2026 for entrepreneurs whose sales value (including VAT) exceeded PLN 200 million in 2024.
For other businesses (including sole proprietors), this obligation will be postponed until 1 April 2026.
However, businesses whose sales value (including VAT) does not exceed PLN 10,000 per month will be able to postpone introduction of KSeF until 1 January 2027.
It is important to note that from 1 February 2026, all businesses, regardless of when they must begin issuing structured invoices, will be required to receive invoices via KSeF. This means that even companies not yet subject to mandatory KSeF issuance must still ensure they have access to the system to properly receive and process invoices.
Contractual Implications
The implementation of KSeF is not only a technical issue, but also requires contracts with contractors to be changed or adjusted, in order to e.g.:
- eliminate references to existing forms of invoice delivery, which will no longer apply,
- adjust settlement mechanisms to the new model,
- clarify the procedure of transferring attachments (e.g. specifications, protocols) that cannot be an integral part of an invoice in KSeF,
- clarify the provisions on trade secrets and the transfer of data to the tax authorities (KSeF is a public system),
- ensure the proper functioning of processes, e.g. in the event of a system failure.
Electronic Tax Books
One of the tax changes related to KSEF that may be challenging, especially for accountants, is the obligation to keep records in an electronic form.
As of 1 January 2025, CIT taxpayers and companies that are not legal persons with revenues from the previous year exceeding EUR 50 million, as well as tax capital groups, are required to keep tax books in an electronic form.
As of 1 January 2026, the new obligations will apply to CIT taxpayers and companies that are not legal entities and, for the first time, to PIT taxpayers who settle VAT on a monthly basis.
From 1 January 2027, this obligation will apply to other CIT taxpayers and companies that are not legal entities, as well as PIT taxpayers (including those who settle their accounts on a quarterly basis).
Changes to VAT Corrections
Another change related to the introduction of KSeF will be a modification of the rules for reducing VAT base based on a corrective invoice.
Until now, correction of tax base required agreeing terms with a purchaser. After the new regulations come into force, the correction will be made in the settlement period in which the corrective invoice was issued in KSeF. This change will come into force on 1 February 2026 exclusively for invoices issued in the KSeF system. In the case of invoices other than structured ones, the moment of recognition of such an invoice will remain unchanged.
No Sanctions in 2026
Finally, please note that any penalties and sanctions for non-compliance with KSeF are postponed until 1 January 2027.
Article 106ni of the VAT Act, which provides for financial penalties for violations of KSeF regulations, will enter into force on 1 January 2027, and therefore, throughout 2026, any violations will not entail any liability.
Importantly, the regulations also do not provide for criminal and fiscal liability for any offences under KSeF. Article 106ni(4) of the VAT Act explicitly states that in cases of violations of specific KSeF regulations, no proceedings for fiscal offences or fiscal misdemeanors shall be initiated.
It also seems that the supplier’s failure to use the KSeF system will not have any negative consequences for the purchaser, which could include, for example, the inability to deduct input VAT from invoices received that were issued without the mandatory structured form. In this regard, the Polish tax authorities have issued several interpretations that the right to deduct input VAT does not depend on the form of the invoice received.
If you have any questions or concerns regarding the above issue, our law firm will be happy to assist you.
Marcin Balicki, Advocate, contributed to this review.
