Compound interest is often referred to as the eighth wonder of the world due to its power to grow wealth exponentially over time. The concept is simple: you earn interest not only on your initial investment but also on the interest that accumulates over time. This allows your money to grow at an accelerated rate compared to simple interest, which is calculated only on the principal.

To understand compound interest, let’s consider a simple example. If you invest $1,000 at an interest rate of 5% compounded annually, you’ll earn $50 in interest after the first year. In the second year, you’ll earn interest on both your original $1,000 and the $50 in interest, giving you a slightly larger return. Over time, this compounding effect can significantly increase your total returns. For a more detailed explanation and examples, Investopedia offers an easy-to-understand breakdown of compound interest, which you can read here.

The longer you let your money compound, the greater the potential growth. This is why it’s often said that time is your greatest ally when it comes to investing. Starting early allows you to take full advantage of compound interest. For instance, if you start investing in your 20s, your money has several decades to grow, which can lead to substantial wealth by retirement. On the other hand, if you start investing later in life, you’ll have less time for compounding to work its magic.

Compound interest applies to a variety of financial products, including savings accounts, bonds, and investment accounts like 401(k)s and IRAs. Many people use retirement accounts to take advantage of compound interest because the money can grow tax-free until it’s withdrawn in retirement. Compound interest can also work against you if you carry high-interest debt, such as credit card balances, where interest compounds on the unpaid balance, making it harder to pay off over time.

The formula for compound interest is: A=P×(1+rn)ntA = P \times \left( 1 + \frac{r}{n} \right)^{nt}A=P×(1+nr​)nt Where:

  • AAA is the amount of money accumulated after n years, including interest.
  • PPP is the principal amount (the initial money).
  • rrr is the annual interest rate (in decimal).
  • nnn is the number of times the interest is compounded per year.
  • ttt is the time the money is invested or borrowed for, in years.

By regularly contributing to investments and allowing compound interest to grow your savings over time, you can significantly enhance your wealth. The Balance also provides a useful guide on how to leverage compound interest in your savings strategy, available here.