How compound interest builds wealth
Compound interest is interest earned on your interest. In the early years the growth looks modest, but because each year builds on a larger balance, the curve steepens over time. Given enough years, the interest you earn can dwarf the money you put in. This is why starting early matters more than starting big.
The calculator separates your future balance into two parts: the total you contributed and the interest earned on top. Seeing those two figures side by side makes the effect of compounding concrete rather than abstract.
The three levers you control
Three inputs drive your result. Time is the most powerful, because compounding rewards long horizons, so an early start beats a large late one. Your monthly contribution is the lever you control most directly, and raising it steadily has an outsized effect. The rate of return depends on where you invest, and higher returns usually come with higher risk.
Try changing one input at a time to see how sensitive the final number is to each. Adding a few more years, or a slightly larger monthly contribution, often changes the outcome more than chasing a higher rate.
These free tools provide general estimates for educational purposes only and are not financial, tax, or investment advice. For decisions specific to your situation, consult a qualified professional.