Compound Interest Calculator

How compound interest works

Compound interest is "interest on interest": each period, the return is calculated on the accumulated balance (principal + previous interest), not only on the initial amount. The formula is M = C × (1 + i)ⁿ.

That is why time is the investor's greatest ally — the earlier you start, the bigger the exponential effect.

Time and consistency win

Regular monthly contributions, even small ones, make a huge difference. Reinvesting returns instead of withdrawing them is what makes wealth grow exponentially.

How to use the calculator

Fill in the initial amount, the monthly contribution, the monthly interest rate and the period in months or years. The result shows the final amount, the total invested and the accumulated interest, plus a chart and a month-by-month breakdown so you can visualize the growth over time.