Free compound interest calculator
See how compound interest multiplies your savings
- 1
Enter amounts
How much you start with and how much you add each month.
- 2
Choose the time
How many years you want to keep the money invested.
- 3
See the result
See how much you earn and what's left after capital gains tax.
How much will your savings grow?
The amount you invest right away.
We add the contribution at the start of every month.
The longer it is, the stronger compounding works.
We assume 6% a year. Options show the average up to 2025, in PLN with dividends. Past returns don't guarantee future ones.
Your result
In 20 years, your savings could be worth
PLN 259,894
After the 19% capital gains tax you withdraw PLN 235,214. That's about PLN 158,606 in today's money.
- Your contributions
- PLN 130,000
- Investment gain
- PLN 129,894
- Capital gains tax (19%)
- −PLN 24,680
Compounding adds PLN 129,894 for you
The gain is 100% of what you pay in. The longer you invest, the bigger the share of the result that comes from gains.
How your savings grow
Tip: time is on your side – at 6% a year, PLN 500 a month for 30 years beats PLN 1,000 a month for 20 years.
This is a simulation, not a promise of returns. Real returns change from year to year.
What is compound interest?
Compound interest means earning on your earlier gains. Every gain that stays invested starts working for the next one – that's why the result grows faster and faster.
Time matters most
The longer money works, the bigger the share of the result that comes from gains, not contributions.
Consistency beats market timing
A fixed monthly contribution builds wealth without guessing the best moment to buy.
Costs and taxes compound too
High fees and capital gains tax weaken compounding. See how much you can gain with an IKE or IKZE.
Track your real results in FundStat
Import transactions from your broker and see how your portfolio really grows.
Frequently asked questions
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