See how fast overpayments shorten your mortgage
Enter key mortgage parameters, add a recurring monthly overpayment and a one-off top-up – the lightning calculator instantly shows interest savings and the new payoff date.
We use the current nominal rate and leave more advanced inputs (fees, multiple overpayment scenarios) to the full calculator. It is a quick preview before you talk to the bank.
- Time saved
- 7 years and 7 mo.
- Interest saved
- 212 532 zł
- New payment
- 3765 zł
- Total overpayments
- 133 200 zł
From paź 2049 to mar 2042.
Difference between interest without overpayments and with your lightning plan.
Without overpayments the instalment is about 3765 zł.
Total extra contributions used in this lightning analysis.
How does lightning mode work?
The lightning version focuses on essential inputs only. Enter the remaining balance, interest rate, term and plan two overpayments: recurring monthly and a single top-up. We estimate the shorter schedule, interest savings and the new payment.
- Enter the remaining balance and current nominal rate (WIBOR/WIRON + margin).
- Set the monthly overpayment and a one-off contribution such as a bonus.
- Choose whether to shorten the term or reduce the payment and review the result.
Need multiple scenarios, extra costs and CSV export? Use the full loan overpayment calculator.
Enter the month number from today when you plan the extra payment. Example: 12 means the bonus after a year.
7 years and 7 mo. Interest savings of about 212 532 zł with extra contributions totalling 133 200 zł.
The lightning calculator gives an indicative effect using current rates. The full version lets you build multiple scenarios, add extra costs and export CSV reports.
Interest saved
212 532 zł
Total extra contributions: 133 200 zł
Schedule reduction
7 years and 7 mo.
From paź 2049 to mar 2042
Monthly instalment
3765 zł
Without overpayments: 3765 zł
Total loan cost
871 849 zł
Without overpayments: 1 084 381 zł
| Metric | Without overpayments | With overpayments |
|---|---|---|
| Monthly instalment | 3765 zł | 3765 zł |
| Total loan cost | 1 084 381 zł | 871 849 zł |
| Total interest | 564 381 zł | 351 849 zł |
| Payoff date | paź 2049 | mar 2042 |
| Payoff duration | 288 mo. | 197 mo. |
| Total overpayments | 0 zł | 133 200 zł |
What next?
- Review your loan agreement for overpayment limits or fees – capture them in the full calculator.
- Save the report and compare it with alternative strategies (e.g. investing the surplus).
- Update the inputs after each WIBOR/WIRON change to keep the schedule accurate.
What to double-check before overpaying?
- Bank limits: some lenders allow free overpayments only after 3–5 years. Check for early repayment fees.
- Insurance and fees: mandatory policies or premium accounts can eat into the benefit. Add them in the full calculator.
- Emergency fund: before sending all spare cash to the bank, build a 3–6 month safety buffer.
Compare with other strategies
Overpayments are one of several budget levers. Before you decide, stack them against investing the surplus or refinancing:
Ready for full analysis?
The full overpayment calculator handles multiple scenarios, extra costs, CSV export and advisor-ready reports. Perfect for bank negotiations.
Open full version