Investing 101: The Concept Of Compounding
  1. Investing 101: Introduction
  2. Investing 101: What Is Investing?
  3. Investing 101: The Concept Of Compounding
  4. Investing 101: Knowing Yourself
  5. Investing 101: Preparing For Contradictions
  6. Investing 101: Types Of Investments
  7. Investing 101: Portfolios And Diversification
  8. Investing 101: Conclusion

Investing 101: The Concept Of Compounding


Albert Einstein called compound interest "the greatest mathematical discovery of all time". We think this is true partly because, unlike the trigonometry or calculus you studied back in high school, compounding can be applied to everyday life.

The wonder of compounding (sometimes called "compound interest") transforms your working money into a state-of-the-art, highly powerful income-generating tool. Compounding is the process of generating earnings on an asset's reinvested earnings. To work, it requires two things: the re-investment of earnings and time. The more time you give your investments, the more you are able to accelerate the income potential of your original investment, which takes the pressure off of you.

To demonstrate, let's look at an example:

If you invest $10,000 today at 6%, you will have $10,600 in one year ($10,000 x 1.06). Now let's say that rather than withdraw the $600 gained from interest, you keep it in there for another year. If you continue to earn the same rate of 6%, your investment will grow to $11,236.00 ($10,600 x 1.06) by the end of the second year.

Because you reinvested that $600, it works together with the original investment, earning you $636, which is $36 more than the previous year. This little bit extra may seem like peanuts now, but let's not forget that you didn't have to lift a finger to earn that $36. More importantly, this $36 also has the capacity to earn interest. After the next year, your investment will be worth $11,910.16 ($11,236 x 1.06). This time you earned $674.16, which is $74.16 more interest than the first year. This increase in the amount made each year is compounding in action: interest earning interest on interest and so on. This will continue as long as you keep reinvesting and earning interest.

Starting Early
Consider two individuals, we'll name them Pam and Sam. Both Pam and Sam are the same age. When Pam was 25 she invested $15,000 at an interest rate of 5.5%. For simplicity, let's assume the interest rate was compounded annually. By the time Pam reaches 50, she will have $57,200.89 ($15,000 x [1.055^25]) in her bank account.

Pam's friend, Sam, did not start investing until he reached age 35. At that time, he invested $15,000 at the same interest rate of 5.5% compounded annually. By the time Sam reaches age 50, he will have $33,487.15 ($15,000 x [1.055^15]) in his bank account.

What happened? Both Pam and Sam are 50 years old, but Pam has $23,713.74 ($57,200.89 - $33,487.15) more in her savings account than Sam, even though he invested the same amount of money! By giving her investment more time to grow, Pam earned a total of $42,200.89 in interest and Sam earned only $18,487.15.

Editor's Note: For now, we will have to ask you to trust that these calculations are correct. In this tutorial we concentrate on the results of compounding rather than the mathematics behind it. (If you'd like to learn more about how the numbers work, see Understanding The Time Value Of Money.)

Both Pam and Sam's earnings rates are demonstrated in the following chart:




You can see that both investments start to grow slowly and then accelerate, as reflected in the increase in the curves' steepness. Pam's line becomes steeper as she nears her 50s not simply because she has accumulated more interest, but because this accumulated interest is itself accruing more interest.



Pam's line gets even steeper (her rate of return increases) in another 10 years. At age 60 she would have nearly $100,000 in her bank account, while Sam would only have around $60,000, a $40,000 difference!


When you invest, always keep in mind that compounding amplifies the growth of your working money. Just like investing maximizes your earning potential, compounding maximizes the earning potential of your investments - but remember, because time and reinvesting make compounding work, you must keep your hands off the principal and earned interest.
Investing 101: Knowing Yourself

  1. Investing 101: Introduction
  2. Investing 101: What Is Investing?
  3. Investing 101: The Concept Of Compounding
  4. Investing 101: Knowing Yourself
  5. Investing 101: Preparing For Contradictions
  6. Investing 101: Types Of Investments
  7. Investing 101: Portfolios And Diversification
  8. Investing 101: Conclusion
RELATED TERMS
  1. Warrant

    A derivative that confers the right, but not the obligation, ...
  2. Swap

    A derivative contract through which two parties exchange financial ...
  3. Bull Call Spread

    An options strategy that involves purchasing call options at ...
  4. Board Of Directors - B Of D

    A group of individuals that are elected as, or elected to act ...
  5. Hedge

    Making an investment to reduce the risk of adverse price movements ...
  6. Markdown

    The difference between the highest current bid price among dealers ...
RELATED FAQS
  1. What is a derivative?

    A derivative is a contract between two or more parties whose value is based on an agreed-upon underlying financial asset, ... Read Full Answer >>
  2. What is finance?

    "Finance" is a broad term that describes two related activities: the study of how money is managed and the actual process ... Read Full Answer >>
  3. What is after-hours trading? Am I able to trade at this time?

    After-hours trading (AHT) refers to the buying and selling of securities on major exchanges outside of specified regular ... Read Full Answer >>
  4. What is the 'Rule of 72'?

    The 'Rule of 72' is a simplified way to determine how long an investment will take to double, given a fixed annual rate of ... Read Full Answer >>
  5. What is a stock split? Why do stocks split?

    All publicly-traded companies have a set number of shares that are outstanding on the stock market. A stock split is a decision ... Read Full Answer >>
  6. Do hedge funds invest in commodities?

    There are several hedge funds that invest in commodities. Many hedge funds have broad macroeconomic strategies and invest ... Read Full Answer >>
Hot Definitions
  1. Black Swan

    An event or occurrence that deviates beyond what is normally expected of a situation and that would be extremely difficult ...
  2. Inverted Yield Curve

    An interest rate environment in which long-term debt instruments have a lower yield than short-term debt instruments of the ...
  3. Socially Responsible Investment - SRI

    An investment that is considered socially responsible because of the nature of the business the company conducts. Common ...
  4. Presidential Election Cycle (Theory)

    A theory developed by Yale Hirsch that states that U.S. stock markets are weakest in the year following the election of a ...
  5. Super Bowl Indicator

    An indicator based on the belief that a Super Bowl win for a team from the old AFL (AFC division) foretells a decline in ...
Trading Center