Einstein reportedly called it the eighth wonder of the world. “He who understands it, earns it… he who doesn’t… pays it.”
The Snowball Effect
Compound interest is the principle that your interest earns interest. It turns linear growth into geometric growth. Time, not timing, is the critical variable here.
A Tale of Two Investors
Consider two investors, Jack and Jill.
- Jack starts at 25, invests $200/month until 35, then stops.
- Jill starts at 35, invests $200/month until 65.
Despite investing for 30 years vs Jack’s 10, Jill often ends up with less money. That is the power of starting early. That is the power of compounding.
The Rule of 72
Divide 72 by your annual return rate to see how many years it takes to double your money. At 8%, your money doubles every 9 years.
Inflation: The Silent Killer
Compounding works against you with inflation. Cash sitting in a savings account earning 0.1% is technically losing value if inflation is at 3%. You must invest to preserve purchasing power.
Start Today
You don’t need thousands to start. You need consistency. Automate your savings. Index funds, ETFs, or even high-yield savings accounts are better than under the mattress.
Run the numbers yourself with our Compound Interest Simulator.