APR (RRSO) Calculator
Calculate the real annual cost of credit — exactly as banks report APR in Polish loan ads.
APR (Annual Percentage Rate, Polish: RRSO) is the total cost of credit expressed as an annualized percentage. It includes the nominal interest rate, commission, insurance and all mandatory fees spread over the loan term. The kreddo.pl calculator uses Newton–Raphson iteration to solve the APR equation defined in Annex 4 of the Polish Consumer Credit Act — converging to precision within 10⁻⁸ in 5–20 iterations.
Monthly installment
PLN 641
APR (RRSO)
11.84%
Total interest
PLN 3,064
Total cost
PLN 23,564
* APR calculated per the Polish Consumer Credit Act — includes nominal rate, commission, insurance and all mandatory fees spread over the loan term.
Frequently asked questions
What is APR (RRSO)?
APR — the annual percentage rate — is the total cost of credit expressed annually as a percentage of the loan amount. It combines nominal interest, commission, origination fees, mandatory insurance and other costs. In Poland it is called RRSO and defined in the Consumer Credit Act (Dz.U. 2011/126/715).
APR vs nominal interest rate — what is the difference?
Nominal interest is the headline rate (e.g. 9%). APR adds commissions, insurance and other costs and expresses them as an effective annual rate. A loan with 9% nominal + 5% commission may have 15–18% APR. Always compare offers using APR, not nominal rate.
How is APR calculated?
APR solves an equation iteratively: amount received = Σ (installment / (1+r)^(t/12)). The kreddo.pl calculator uses Newton–Raphson — starting from 10%, it converges in 5–20 iterations to the exact rate matching the Consumer Credit Act formula.
Why do payday loans have 500–1000% APR?
APR is an annual rate. A 30-day payday loan with 15% commission has an annualized equivalent of 12 × 15% = 180% for commission alone. Add interest and fees, and APR reaches 300–1000%. You will not actually pay 500% — you pay ~15–20% of the amount — but APR shows how expensive the loan would be on an annual basis.