How to calculate interest on a term deposit
- 1.
Enter the amount and rate
Type the amount you want to deposit in PLN and the annual interest rate from the bank’s offer.
- 2.
Set the term
Enter the term in months, or switch to days for 30-, 90- or 180-day deposits.
- 3.
Choose compounding
Pick interest paid at maturity, or monthly, quarterly or yearly compounding, and keep the 19% Belka tax switched on unless the account is tax-free.
- 4.
Read your net profit
Check gross interest, the tax withheld, your net profit, the amount at maturity and the effective net annual rate.
How deposit interest is calculated
Polish banks quote deposit rates as a nominal annual rate. The interest for a term set in months is amount × rate × months / 12; for a term set in days it is amount × rate × days / 365 (a few banks use a 360-day year). The bank then withholds 19% tax and pays out the rest.
| Deposit of PLN 10,000 | Gross interest | Tax 19% | Net profit |
|---|---|---|---|
| 12 months at 6%, paid at maturity | PLN 600.00 | PLN 114.00 | PLN 486.00 |
| 12 months at 6%, compounded monthly | PLN 613.53 | PLN 116.56 | PLN 496.97 |
| 3 months at 5% | PLN 125.00 | PLN 23.75 | PLN 101.25 |
| 90 days at 5% (365-day year) | PLN 123.29 | PLN 23.43 | PLN 99.86 |
So a headline rate of 6% becomes a net return of 4.86% a year - the tax takes almost a fifth of your interest. Another example: PLN 50,000 for 6 months at 5.5% earns PLN 1,375 gross and PLN 1,113.75 net.
The Belka tax explained for foreigners
Interest on bank accounts and deposits in Poland is taxed at a flat 19% (Art. 30a of the Personal Income Tax Act). It is nicknamed podatek Belki after Marek Belka, the finance minister who introduced it in 2002. The bank acts as the tax remitter: it withholds the tax automatically on the day interest is credited, so you do not report deposit interest in your annual PIT return.
The tax applies to anyone holding money in a Polish bank, including foreign residents. If you are tax resident in another country, a double tax treaty may change how the interest is taxed there - ask a tax adviser if that is your situation.
Rounding: unlike most Polish taxes, which are rounded to whole złoty, tax on bank interest is rounded to the full grosz (Art. 63 § 1a of the Tax Ordinance). The calculator does the same at every compounding, exactly as banks do.
Why compounding frequency matters
With monthly compounding the bank credits interest every month, takes the tax each time and adds the net interest to your balance, so next month you earn interest on it too. At the same nominal rate that gives slightly more than one payment at maturity: PLN 496.97 instead of PLN 486 on PLN 10,000 at 6% over a year. The difference grows with the rate and the term, but it is small compared with the effect of a better rate. If you plan to keep rolling deposits over for many years, the compound interest calculator shows the long-term picture.
What to check before opening a deposit in Poland
- Promotional rates often apply only to new money, a capped amount or a short term such as 3 months.
- Breaking the deposit early usually means losing all or most of the interest, though your capital is returned.
- Deposit guarantee - money in Polish banks is protected by the Bank Guarantee Fund (BFG) up to the equivalent of EUR 100,000 per person per bank.
- Inflation - if your net rate is below inflation, your savings lose purchasing power. Compare with Polish treasury bonds, which can be linked to inflation, or check past price rises in the inflation calculator.
Frequently asked questions
How much will I earn on PLN 10,000 at 6% for a year?
+
Gross interest is PLN 600, the Belka tax is PLN 114 and your net profit is PLN 486 if interest is paid at maturity.
What is the Belka tax?
+
It is the common name for the 19% flat tax on interest and other capital gains in Poland. For deposits the bank withholds it automatically when interest is credited.
Do I have to declare deposit interest in my Polish tax return?
+
No. The bank withholds and pays the 19% tax for you, so deposit interest does not go into your annual PIT return.
Is the tax rounded to whole złoty?
+
Not for bank interest - the tax base and the tax are rounded to the nearest grosz, and the calculator follows that rule.
What does monthly compounding mean?
+
Net interest is added to your balance every month and earns interest itself. On PLN 10,000 at 6% the yearly net profit rises from PLN 486 to about PLN 497.
Do banks use 365 or 360 days in a year?
+
Most Polish banks use 365 days, but some use 360, which gives slightly higher interest. Check the deposit terms and pick the right option in the calculator.
Updated: