Maximum interest rate calculator Poland 2026 — art. 359 CC

The maximum capital interest rate (art. 359 §2¹ Civil Code) = 2 × NBP reference rate + 3.5 pp. In 2026, with the NBP rate at 5.75%, the cap is 11.5% + 3.5% = 15% per annum. Contractual interest cannot legally exceed this amount.

Maximum late-payment interest (art. 481 §2¹ CC) = 2 × (NBP rate + 5.5 pp). In 2026: 2 × (5.75% + 5.5%) = 22.5% per annum. It applies when payment is overdue and the parties have not agreed on a specific rate.

No — art. 359 §2² CC: if the parties set higher interest, only the statutory maximum is due. The excess clause is void under art. 58 §1 CC. This is the Polish anti-usury rule.

Statutory interest (art. 359 §2 CC) = NBP rate + 3.5 pp = 9.25% (2026). Statutory late-payment interest (art. 481 §2 CC) = NBP rate + 5.5 pp = 11.25% (2026). Maximum rates = 2 × statutory = 15% or 22.5% for late payment.

The NBP reference rate has been 5.75% since 4 October 2023 following a decision of the Monetary Policy Council. Always check the current rate at nbp.pl before making financial decisions.

Usury means stipulating or collecting interest or fees above the statutory maximum. Art. 304 of the Polish Penal Code criminalises usury as a criminal offence carrying up to 5 years imprisonment. It applies to any contract — loans, credit, promissory notes — not only bank products.

Interest = principal × rate (%) × days / 365. Example: PLN 10,000, 15% per annum, 180 days: 10,000 × 0.15 × 180/365 = PLN 739.73. Always use 365 days for annual rates (366 in a leap year).

The calculator uses simple (linear) interest, not compound. For long periods (over a year) compound interest would be higher. Private loan contracts typically use simple interest; bank loans may capitalise interest.

The statutory cap does not apply to: tax interest (governed separately), interest in professional transactions between merchants excluded from CC, commercial transactions covered by the Late Payment Act.

Mode "Calculate interest": enter principal, rate, and days — the calculator returns the interest amount and warns if the rate exceeds the legal maximum. Mode "Current rates": shows the applicable statutory caps in Poland.