Compound Interest Calculator

Compound growth is interest earning interest: each period's gains join the principal and earn in the next period. This calculator applies the standard compounding formula to your starting amount, annual rate, compounding frequency, and timeframe, then layers in optional regular contributions to show their full effect.

The growth curve tells the real story. Early years look modest, then the curve bends upward as compounding takes over — which is why starting early usually matters more than chasing a slightly higher rate later. Comparing scenarios, such as monthly versus annual contributions, makes the advantage of consistency tangible.

These projections are mathematical illustrations, not predictions. Real investments carry risk, fees, and taxes, and past performance never guarantees future returns. Use the calculator to build intuition about time and consistency, and speak with a qualified adviser before making investment decisions.