Your Money Is Growing While You Sleep (Here's the Math)

Imagine waking up and your bank account is slightly bigger than yesterday — and tomorrow it grows even faster than today. That's compound interest, and here's how it works. Put a thousand dollars in an account earning ten percent a year. Simple interest pays a flat hundred dollars every year — same amount, forever. Compound interest is different. Year one: interest on your thousand. Year two: interest on your thousand plus last year's interest. The base keeps growing, so each new round of interest grows too. It's like a snowball rolling downhill — the bigger it gets, the more snow it picks up, faster and faster. Quick mental trick: the Rule of 72. Divide 72 by your interest rate to find how many years to double your money. At seven percent, roughly ten years — so five thousand dollars at age twenty could quietly become eighty thousand by sixty, without adding another cent. It works against you too. Credit card debt compounds daily, turning small balances into big ones surprisingly fast. Every day you wait is a compounding cycle you can never get back.