Every payment linked to the loan enters the RRSO formula: nominal interest, one-off commission, arrangement fee, mandatory loan insurance and anything else the contract makes compulsory. A cost you can avoid — say, a fee for a payment reminder — does not enter the formula. The formula sits in Annex 4 to the consumer credit act; it is a time-value-of-money equation showing how much you effectively pay per 100 PLN of principal per year.
Here is how it plays out. Bank A offers 20 000 PLN over 36 months, 8% nominal rate, 5% commission, no insurance — RRSO around 12%. Bank B: same 20 000 PLN, 6% nominal rate, 12% commission, plus mandatory 2 000 PLN insurance — RRSO around 22%. The ad will feature Bank B's lower rate, but Bank A will save you several thousand PLN.
Fair comparison means comparing by RRSO. If an ad shows „interest from 4.9%" and hides the commission and insurance in small print, it is legal but not honest about the cost. The Kreditano RRSO calculator uses the same formula banks use.
Frequently asked questions
No. The interest rate is the percentage charged on the outstanding principal. RRSO is the full annual cost including commission, insurance and every mandatory fee. RRSO will always be higher than the nominal rate.
Cash loans at banks: 10–15%. Mortgages: 7.6–7.9%. Payday and non-bank loans: 30–80%, in extreme cases up to the statutory anti-usury ceiling (2 × NBP reference rate + 20%, with non-interest costs capped at 45% of principal).
No. The consumer credit act (art. 36a) caps non-interest costs at 45% of the principal in year one and 100% over the whole term. Any offer above these figures is unlawful and you are not obliged to pay the excess.