🏦Bank Deposit Calculator

Deposit calculator — calculate interest and capital gains tax online

Our free deposit calculator lets you check in seconds how much you will earn on a bank deposit. Enter the deposit amount, nominal annual gross interest rate, term, and compounding frequency. The calculator automatically works out gross interest, deducts the Polish capital gains tax (19%), and shows the final net amount at the end of the deposit. You can disable the tax deduction if you want to compare different offers on a gross basis.

Interest compounding — how does it affect deposit returns?

The choice of compounding frequency has a direct impact on your actual return. With monthly or quarterly compounding, interest is credited to the principal regularly and begins generating further interest — this is the compound interest effect. The at-maturity (simple) option corresponds to deposits where interest is paid out once at the end of the agreement. For short deposits the difference is small, but for multi-year deposits more frequent compounding can noticeably increase your return.

Full privacy — calculations done locally

The deposit calculator runs entirely in your browser. No data — deposit amount, interest rate, or term — is sent to any server or stored in external databases. You can use the tool without logging in, without installation, and without any limits.

Frequently asked questions

What is the Polish capital gains tax and how much is it?

The Polish capital gains tax (colloquially called "Belka tax") is a 19% levy on interest earned. Banks automatically deduct it when paying out interest, so only the net amount reaches your account. The calculator computes this amount and displays it separately.

What is the difference between simple and compound interest capitalization?

With simple capitalization (at maturity), interest is calculated once for the entire period and added only at the end of the deposit. With compound capitalization (annual, quarterly, monthly, daily), interest is credited to the principal more frequently and starts generating further interest — the more frequent the compounding, the higher the return at the same nominal rate.

Is my financial data safe?

Yes. All calculations are performed exclusively in your browser. Your deposit amount, interest rate, and any other data are never sent to any server. The tool works fully offline once the page is loaded.