InsiderFlowTools › Compound interest calculator

Compound interest calculator

Enter your starting capital, monthly contribution, expected return and duration: the calculator shows year-by-year growth, separating what you contributed from what interest generated.

Final capital
Total contributed
Interest earned

Indicative calculation for educational purposes: not a forecast nor financial advice.

Compound interest generates gains on previously earned gains: that's why the curve accelerates over the years. A 7% annual return doubles your capital roughly every 10 years (rule of 72).

The return should be read gross of taxes and inflation: as a reference, global equities have historically returned 6–8% real per year over long horizons. No return is guaranteed.

Frequently asked questions

What return should I enter?

For a global equity portfolio, 6–8% a year is the long-term historical average; for balanced portfolios, 4–6% is more realistic. Past performance doesn't guarantee the future.

Does the calculation include taxes and inflation?

No: the result is gross. Capital gains taxes and inflation both reduce your real outcome.

Related terms

What is compound interest?What is dollar cost averaging (DCA)?What is an investment return?