Calculator
Loan repayment calculator
Estimate instalments for a cash loan or another simple instalment loan using your own parameters. One tool covers payment and financing costs without duplicate calculators. An upfront cash-paid fee does not add interest; a financed fee increases principal. This is not an offer, APR/RRSO or creditworthiness assessment.
Calculator
Enter data
Amount/property price, term in months, entered nominal interest rate and known fees. Fields marked with an asterisk are required.
How to use the calculator
- Enter the loan amount received excluding fees. Do not use total repayment as principal.
- Enter the annual nominal rate and term in months. Choose equal or decreasing repayments.
- Enter the upfront fee, its payment method and fixed monthly fees. Check whether the offer has other costs or a changing schedule.
- Calculate, inspect every month and compare with the lender’s information form. Copy includes the breakdown and schedule.
Calculation details
Formula and calculation method
P = loan amount + fee when financed; r = annual nominal rate / 12 / 100. Equal instalment = P × r / (1 − (1 + r)^−n), or P/n at 0%. Decreasing principal = P/n; interest = balance × r. Each month rounds to cents; final principal clears the balance. Cost = interest sum + upfront fee + n × monthly fee. Total repayment = received loan + cost; financed fees are not counted twice.
Worked example
Loan PLN 12,000, 0%, 12 months, upfront fee PLN 1,200 and monthly fee PLN 10: a cash-paid fee gives a payment including fee of PLN 1,010; financing the fee gives PLN 1,110. At 0%, both have a cost of PLN 1,320 and total repayment of PLN 13,320.
Limitations
- Monthly mathematical model in PLN with a constant rate and no payment deferrals. Does not model daily interest, a bank calendar, staged draws, grace periods, payment holidays, balloon loans or overpayments.
- No current offers or reference rates are fetched. For a temporarily fixed or variable rate, future repayments are unknown. Rate comparison means two independent constant-rate simulations, not a forecast.
- APR/RRSO is not calculated. It depends on defined costs and cash-flow timing; a nominal rate or entered-fee total is not a substitute. Statutory cost limits and offer compliance are not checked.
- A cash-paid upfront fee is outside instalments but included in total repayment. Financing it adds interest. Fixed fees are charged throughout the entered term; early-repayment fee refunds are not predicted.
- Rounding each payment can change the final payment. For very small amounts, high rates or long terms, the difference can be larger. Check the first and final payments and the full schedule.
Sources
- Annuity-payment model — project methodology
- UOKiK — mortgage payments, interest rates and simulation limitations
- UOKiK — consumer credit, fees and APR/RRSO
Engine version: 1.0.0 · Last reviewed: 30 September 2026
Frequently asked questions
How do equal and decreasing instalments differ?
With equal payments, principal increases as interest decreases. With decreasing payments, principal is fixed, so the first payment is usually higher. The final payment resolves rounding.
Is nominal interest the same as APR/RRSO?
No. APR/RRSO includes defined costs and timing. This calculator shows payments and costs for the entered scenario; it does not compute APR/RRSO.
Is a financed upfront fee counted twice?
No. It increases principal and interest but enters total repayment once. A cash-paid fee does not increase principal but remains part of total spending.
Are entered amounts sent or saved?
No. Calculations run in your browser. Values are not added to the URL, persistent storage or analytics. You can deliberately copy or print a result.