Przejdź do treści
Liczbnik
Current for 2026Methodology →

Bank Deposit Calculator

Knowing your real after-tax return is essential before committing funds to a bank deposit. This calculator computes gross interest, deducts the 19% Polish capital gains tax (podatek Belki), and shows you exactly how much you will receive at maturity. Just enter three values: principal, annual interest rate, and deposit term in days.

Na tej stronie

How we calculate deposit interest

We use the simple interest formula: Gross Interest = Principal × (Rate / 100) × (Days / 365). Capital Gains Tax = Gross Interest × 0.19. Net Interest = Gross Interest − Tax. Final Amount = Principal + Net Interest. Effective Net Rate = (Net Interest / Principal) × (365 / Days) × 100%.

Example calculation

Deposit: PLN 10,000 at 5% per annum for 365 days. Gross interest: PLN 500.00. Capital gains tax (19%): PLN 95.00. Net interest: PLN 405.00. Final payout: PLN 10,405.00. Effective net rate: 4.05%.

Frequently asked questions

How does the bank deposit calculator work?

Enter your principal amount, the annual interest rate offered by the bank, and the deposit term in days. The calculator computes gross interest, deducts 19% Polish capital gains tax, and shows your net return and final payout.

What formula is used for the calculation?

Gross Interest = Principal × (Rate / 100) × (Days / 365). Tax = Gross Interest × 0.19. Net Interest = Gross Interest − Tax. Final Amount = Principal + Net Interest.

Does the calculator include capital gains tax?

Yes. In Poland, all interest income from bank deposits is subject to a flat 19% capital gains tax (podatek Belki), withheld automatically by the bank. The calculator shows both gross and net figures.

Gross interest: PLN 500. Tax (19%): PLN 95. Net interest: PLN 405. Final payout: PLN 10,405. Effective net rate: 4.05%.

Enter 90 in the Days field. The calculator will prorate the annual rate accordingly: Interest = Principal × (Rate / 100) × (90 / 365). Note that banks always quote rates on an annual basis.

The formula is currency-agnostic. Enter your principal in any currency; the result will be in the same currency. Just make sure the interest rate matches the one quoted by the bank for that specific currency deposit.

It is the real annualised return after tax: (Net Interest / Principal) × (365 / Days) × 100%. It lets you compare deposits of different durations on an equal footing.

No. The calculator is for informational use only. Actual earnings depend on the bank's offer, terms and conditions, and applicable tax rules. Always verify with your bank before opening a deposit.

Multiply the monthly rate by 12 to get the annual rate, then enter that figure into the Rate field along with the number of days. The calculator will prorate accordingly.

A fixed-term deposit locks in your money for a set period at a fixed rate. Early withdrawal usually forfeits interest. A savings account is more flexible but typically offers a variable, lower rate.

Results are for informational purposes only and do not constitute a financial offer or advice. Actual deposit terms, including interest rate, period, and accrual method, are defined by the bank's terms and conditions. The 19% capital gains tax rate reflects Polish law as of the calculator's last update. Consult a financial adviser before making investment decisions.

Related calculators

  • Compound interest calculator

    Calculate compound interest: final value, interest earned and capital growth. Free calculator with monthly, quarterly and yearly compounding.

  • Belka Tax Calculator

    Calculate the Belka tax (19%) on interest, dividends, and capital gains from securities. Find out how much you will pay and how much you keep after tax.

  • Inflation & Purchasing Power Calculator

    Calculate how much your money is worth after inflation. Enter amount, start year, end year and inflation rate — get purchasing power loss instantly. Based on GUS data. Free.

Related articles