Errors in VAT, PIT and ZUS settlements can cost any business dearly. Find out which mistakes occur most often and how to avoid them effectively.
Running your own business is not just about sales and customer service — it also involves dozens of settlement obligations that are easy to overlook or carry out incorrectly. Errors in VAT, PIT and ZUS settlements occur among both new entrepreneurs and those with many years of experience. The consequences can be serious: interest on arrears, administrative penalties, and in extreme cases — a tax audit. In this article we discuss the most common settlement pitfalls and advise on how to protect yourself against them.
VAT is one of the areas where mistakes occur most frequently. Typical errors include: • Deducting VAT from invoices that do not confer the right to deduction (e.g. invoices for catering or accommodation services). • Incorrectly classifying a transaction as VAT-exempt when it should be taxed — and vice versa. • Filing the JPK_V7 file late or making formal errors in its structure. • Overlooking the obligation to correct VAT when the intended use of an asset changes. • Incorrectly settling VAT on the import of services or intra-Community acquisition of goods. From 2026, with mandatory KSeF in place, the formal requirements for invoices have increased significantly. Any discrepancy in the structure of an e-invoice may result in the right to deduct tax being challenged.
Settling personal income tax is another area that generates numerous mistakes. The most frequently encountered errors are: 1. Including in tax-deductible costs expenses that have no connection with business activity. 2. Incorrectly determining the form of taxation — the choice between the tax scale, flat-rate income tax or lump-sum tax should be carefully considered and made within the statutory deadline. 3. Failing to update the form of taxation when the business profile changes. 4. Omitting income from various sources, e.g. from private rental alongside business activity. 5. Incorrectly settling tax reliefs — an incorrect amount or lack of required supporting documents. From 2026, taxpayers keeping full accounting books must also remember the mandatory submission of JPK_CIT, while micro-entrepreneurs keeping KPiR must submit JPK_PKPIR. Errors in these files may serve as grounds for the US (tax office) to initiate verification proceedings.
ZUS is another institution with which entrepreneurs have regular obligations. The most common errors in this area are: • Late payment of contributions — even a one-day delay generates interest. • Errors when registering employees or contractors for social insurance (ZUS ZUA, ZUS ZZA). • Incorrectly determining the assessment base for the health insurance contribution, the amount of which in 2026 depends on the form of taxation and income earned. • Overlooking the obligation to deregister an employee after the end of cooperation. • Failing to verify whether a given contract should be treated as an employment contract, which affects the obligation to pay full contributions. The health insurance contribution remains one of the more complex issues — its annual settlement requires particular attention.
Incorrectly settling tax-deductible costs is one of the most common reasons for corrections to tax returns. Entrepreneurs frequently make the following errors: • Including private or mixed expenses in costs without adequate documentation of their business purpose. • Failing to keep a vehicle mileage log when settling a passenger car used for mixed purposes. • Depreciating fixed assets using incorrect rates or the wrong KŚT classification. • Treating as current expenses costs that should increase the value of a fixed asset. • Settling costs in the wrong tax year — the accrual basis is sometimes confused with the cash basis. Properly documenting every business expense is the foundation of a safe settlement.
Not only substantive but also formal errors can cause problems. The most common ones include: • Issuing invoices with incorrect data — wrong NIP, address or VAT rate. • Failing to issue invoices or credit notes on time. • Incomplete or carelessly maintained records of accounting documents. • Overlooking the obligation to archive documents for the period required by law (as a rule, 5 years). • Inconsistencies between declarations and the JPK files submitted. Since the introduction of mandatory KSeF, every domestic invoice issued between VAT taxpayers must be submitted to the Ministry of Finance system. Technical errors or failure to comply with this obligation may result in financial penalties.
Prevention is decidedly cheaper than correction. Here are a few practical rules that will help minimise the risk of errors: 1. Keep up-to-date records — do not put off documents until the end of the month or quarter. 2. Track regulatory changes — 2026 has brought significant changes in the areas of KSeF, JPK and the health insurance contribution. 3. Use professional accounting services — an accounting firm not only records documents but also actively advises and warns against risks. 4. Verify data before submitting declarations — every inconsistency is a potential signal for the US. 5. Ask before making a decision — classifying a transaction for tax purposes before it takes place is far simpler than correcting it afterwards. Regular cooperation with an experienced accountant is an investment that protects the business and allows you to focus on its growth.
Settlement errors happen to everyone — but not everyone has to bear their consequences. The key is awareness of the most common pitfalls and using expert support. If you want to be sure that your company is settling VAT, PIT, ZUS and costs correctly, contact the Danexis accounting firm in Wrocław. Call +48 780 760 666, write to kontakt@danexis.pl or visit us at ul. Braniborska 74/20 We will be happy to discuss your situation and propose a solution tailored to your company's needs.