Calculator
Polish bank deposit calculator
Estimate deposit maturity value, gross interest, tax and net interest. Data is processed only in your browser, and the page explains the formula and limitations of the result.
Calculator
Enter data
Capital, annual rate, term in months and investment income tax rate. Fields marked with an asterisk are required.
How to use the calculator
- Enter the required data: capital, annual rate, term in months and investment income tax rate.
- Check the values and select “Calculate”.
- Review the primary result and the detailed calculation components.
Calculation details
Formula and calculation method
Gross interest = capital × annual rate × months ÷ 12. Net interest = gross interest × (1 − tax rate).
Worked example
A PLN 10,000 deposit for 6 months at 6% produces PLN 300 gross interest before tax and bank rounding.
Limitations
- A bank may compound, round and tax interest at different times or change the rate after renewal.
Sources
Engine version: 1.0 · Last reviewed: 3 August 2026
Frequently asked questions
Is the entered data sent to a server?
No. The calculation runs locally in your browser and the values are not saved by default.
Is the result definitive?
Not always. A bank may compound, round and tax interest at different times or change the rate after renewal.