Why compound interest matters more than rate
Compound interest is earning interest on previously earned interest. Over one year, a 5% rate compounded monthly beats a 5% simple rate by only 0.12 percentage points. Over 30 years that gap widens enormously: $10,000 at 5% simple grows to $25,000, while 5% compounded monthly reaches $44,816 — a 79% larger outcome from the same starting balance. This is why Einstein allegedly called compound interest the eighth wonder of the world. The lesson for savers is not to chase the highest APY at all costs but to start early, contribute consistently, and let time work. An investor starting at 25 with $300 per month at 7% reaches $720,000 by 65; starting at 35 with $600 per month — twice the contribution — reaches $680,000. Starting early beats contributing more later.