Miss a tax deadline and you will pay interest. Find out what obligations await your business in 2026 – from VAT and JPK to ZUS contributions and annual CIT settlements.
The year 2026 brings entrepreneurs an exceptionally dense schedule of fiscal obligations. Mandatory KSeF, new JPK_CIT and JPK_PKPIR structures, and the unchanged rhythm of VAT declarations and ZUS contributions create a calendar that is easy to overlook – especially amid the rush of daily tasks. In this article we have gathered the most important 2026 tax deadlines for sole traders, sp. z o.o. companies and other entities, so that you can plan your finances and avoid costly delays.
VAT taxpayers settle on a monthly or quarterly basis. The JPK_V7M declaration (monthly) must reach the urząd skarbowy by the 25th day of the month following the settlement period. Quarterly taxpayers submit JPK_V7K by the same deadline – by the 25th day of the month after the end of the quarter. Key dates for monthly filers: • 26 January 2026 – JPK_V7M for December 2025 • 25 February 2026 – JPK_V7M for January • 25 March 2026 – JPK_V7M for February • 27 April 2026 – JPK_V7M for March (the 25th falls on a Sunday) In every case, the VAT due must be paid at the same time as the file is submitted. Late filing results in interest for delay and the risk of verification proceedings being initiated.
From 2026, the Krajowy System e-Faktur (KSeF) becomes mandatory for all active VAT taxpayers. This means that every sales invoice must be issued through the Ministry of Finance system and assigned a KSeF number. The most important practical consequences: • Paper invoices and PDFs sent outside KSeF will not be recognised as valid sales documents. • The VAT payment deadline is calculated from the date the invoice is accepted by the KSeF system. • Failure to integrate your software with KSeF carries financial penalties. If your company has not yet completed its KSeF implementation, it is worth acting immediately – both on the technical side (software) and the procedural side (document workflow, staff training).
Entrepreneurs settling personal income tax have several key deadlines in 2026: 1. Monthly PIT advance payments – due by the 20th day of the following month for the preceding month (e.g. for January, by 20 February). 2. Quarterly advance payments – for taxpayers entitled to quarterly settlements, by the 20th day of the month after the end of the quarter. 3. Annual tax return PIT-36 or PIT-36L for 2025 – the deadline falls on 30 April 2026. 4. Taxpayers settling on a lump-sum basis submit PIT-28 also by 30 April 2026. Entrepreneurs on the progressive tax scale or flat tax pay the difference between the tax due and the total advance payments no later than on the day the return is filed. It is advisable to set aside the necessary funds well in advance.
Sp. z o.o. companies and other legal entities settling CIT must account for new obligations arising from JPK_CIT in 2026. Main CIT deadlines: • Monthly CIT advance payments – by the 20th day of each month for the preceding month. • CIT-8 annual return for the 2025 tax year – by the end of March 2026 (for entities whose tax year coincides with the calendar year). • Additional tax payment resulting from the annual return – by the CIT-8 filing deadline. JPK_CIT is a new electronic structure covering accounting books. In 2026 the obligation applies to CIT taxpayers who have exceeded a specified revenue threshold. The file is submitted to the urząd skarbowy together with the annual return or upon a separate request. Failure to meet this obligation carries serious penalties.
The obligation to pay ZUS contributions applies to virtually every entrepreneur. Deadlines depend on the form of business activity: • Sole traders (without employees) – contributions for a given month are due by the 20th day of the following month. • Employers with employees – the deadline is shortened to the 15th day of the following month. • Sp. z o.o. companies without an entrepreneur-shareholder – by the 15th day of the following month for employees. The health contribution in 2026 continues to depend on the form of taxation and income. Entrepreneurs on the progressive tax scale and flat tax settle the annual contribution via the ZUS DRA or RCA form, with a possible additional payment or overpayment to be reconciled. It is worth monitoring your income on an ongoing basis to avoid surprises at the annual settlement.
From 2026, taxpayers keeping a podatkowa księga przychodów i rozchodów (KPiR) may be required to submit the JPK_PKPIR structure. This obligation is being introduced gradually and covers successive groups of entrepreneurs depending on the scale of their activity. What you should know: • JPK_PKPIR contains detailed data on revenues and costs in a standardised XML format. • The file is submitted at the request of the tax authority or within the deadlines arising from the regulations. • Errors in the file structure may result in a request for correction or an order penalty. Entrepreneurs using an external accounting firm should ensure that the software and processes used by the firm are already adapted to the new JPK requirements.
The 2026 tax deadlines require exceptional attention – new obligations regarding KSeF, JPK_CIT and JPK_PKPIR overlap with the standard rhythm of VAT, PIT, CIT and ZUS. Planning your calendar in advance allows you to avoid interest charges and penalties. If you want to be certain that your business does not miss any deadline, contact the Danexis accounting firm – call +48 780 760 666 or write to kontakt@danexis.pl. We will be happy to discuss your situation and propose a service tailored to the needs of your business.