Albert Einstein famously called compound interest the "eighth wonder of the world." Understanding how simple yield increments accumulate wealth over decades is foundational to personal finance planning.
What is Compound Interest?
Simple interest only calculates returns based on the principal deposit. Compound interest calculates yield returns on the accumulated interest of prior compounding periods as well as the principal sum.
The compound interest equation is:
A = P * (1 + r / n) ^ (n * t)
Where A is the future portfolio value, P is principal, r is rate, n is compounding frequency, and t is years.
How to Leverage Compound Interest
- Start Early: Time is the exponent in the equation. Doubling your years of saving doesn't double returns—it multiplies them.
- Increase Frequency: Monthly compounding produces slightly larger returns than quarterly or annual cycles.
- Reinvest Dividends: Reinvesting returns keeps interest loops uninterrupted.