CalcKitHow to Use the Compound Interest Calculator
Compound interest is often called the eighth wonder of the world: you earn interest not only on your original money but on all the interest added before. Over years and decades, that snowball effect turns modest regular savings into serious wealth โ which is why starting early beats investing more later.
Enter your initial investment, the expected annual interest rate, the number of years, and any monthly contribution, then press Calculate Growth. You'll see the projected future value, how much you personally put in, how much is pure interest, and a year-by-year growth table showing the snowball in action.
Two insights the table makes obvious: time matters more than timing โ doubling the years roughly quadruples the interest at typical rates; and regular monthly contributions usually contribute more than the starting lump sum. Even small rate differences compound enormously over 20โ30 years, so compare savings accounts and funds carefully.
A reality check: this calculator shows nominal growth before inflation and tax. At 3% inflation, money doubles in purchasing power only when it grows well above that rate โ so treat the projection as a planning guide. To see the flip side (what borrowing costs you), try our EMI / Loan Calculator.