Calculator
Mortgage repayment calculator
Plan a property purchase: price minus the down payment gives the loan amount, while a financed fee increases principal. Compare equal and decreasing repayments, add known fees and inspect the schedule. The alternative scenario changes the rate throughout the model; it does not forecast an index or the rate after a fixed-rate period.
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 price, cash down payment and separately known purchase costs. PCC tax and notarial fees are not calculated automatically.
- 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.
- Optionally compare another entered rate. Both remain constant throughout the model. Confirm the schedule and costs with the bank.
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
Price PLN 500,000, down payment PLN 100,000, loan PLN 400,000, 0% rate, 200 months and no fees: payment PLN 2,000, interest PLN 0, total repayment PLN 400,000. Down payment is 20% of price, LTV 80%, and total purchase/repayment budget PLN 500,000.
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.
- LTV uses the entered price, not a bank valuation, and includes a financed fee. Down payment or LTV does not confirm approval. Enter purchase and insurance costs yourself; taxes are not calculated.
- 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.