Business running costs calculator — Polish sole proprietorship 2026

ZUS is the Polish social insurance system. Full ZUS social contributions for a sole trader in 2026 are approximately PLN 1,121/month. The health contribution is approx. PLN 381/month minimum (or 4.9% of income on flat tax). Total mandatory ZUS costs start from about PLN 1,502/month.

The flat tax is a form of income taxation for sole proprietors with a fixed 19% rate regardless of income level. It is advantageous above approximately PLN 160,000/year income, as it avoids the progressive tax brackets (12%/32%).

Yes — ZUS social contributions reduce your taxable income base. The health contribution cannot be deducted from tax since 2022, but 50% of it can be treated as a business cost under the flat tax scheme (up to approx. PLN 11,600/year).

Fixed costs include mandatory ZUS contributions (social + health), office rent or home-office expenses, accounting fees, phone/internet subscriptions, insurance, and any other regular monthly business expenses that do not vary with revenue.

The cost ratio shows what percentage of revenue goes to fixed costs. A ratio above 40-50% signals potential profitability issues. Efficient sole proprietorships typically keep fixed costs below 25-30% of revenue.

The start-up relief exempts new entrepreneurs from ZUS social contributions for the first 6 months. After that, reduced "preferential" contributions apply for 24 months (about PLN 403/month in 2026). Full ZUS kicks in from the third year of operation.

The flat tax (19%) is better when your business costs are high (above 20-25% of revenue), because you pay tax only on net profit after deducting costs. Lump-sum (ryczalt) rates 8.5-15% apply to gross revenue regardless of costs — better for low-cost businesses.

Yes — you can deduct a proportionate share of home costs based on the work area (e.g. 20 m2 of 60 m2 = 33% of rent, utilities, internet). Enter the estimated monthly home-office cost in the "Office rent" field.

No — the calculator assumes full ZUS contributions. If you qualify for Maly ZUS Plus (reduced contributions based on prior-year income), enter your actual monthly ZUS amounts in the form fields. Use the separate Maly ZUS Plus calculator for those figures.

The result is an estimate based on the values you enter. It does not account for all deductible expenses, annual ZUS adjustments, or advance tax payments. For precise tax planning, consult a Polish accountant (ksiegowy).