6 investing key concepts — in plain English

Personal finance is full of concepts that can intimidate newcomers. In reality, being smart with money doesn't require being a mathlete or earning an MBA.

Many complex-sounding financial concepts are actually quite simple, and understanding how they apply to your finances can pay huge dividends.

Here are six financial concepts explained in a straightforward way.

The mathematical magic happens when your principal balance earns interest — which then becomes part of your principal, allowing it to earn interest itself, and the cycle repeats.

Why it matters: A single $1,000 investment earning 6 percent compounded annually will become roughly $4,300 in 25 years. Commit to adding an extra $100 a month in savings and, thanks to compound interest, the balance will swell to more than $70,000.

Opportunity cost is the value of the choice you did not make compared with the option you did chose. For example, the opportunity cost of your morning Danish is the $2 you could have spent on anything else.

Why it matters: Measuring the bottom-line opportunity cost can help you make better financial decisions. For example, which is the better investment: leaving money in a bank account earning 1 percent or less annually in interest, or using the funds to pay off a credit card balance with a 14 percent interest rate?

Dollar-cost averaging is shorthand for investing set amounts of money at regular intervals, such as once per week or month. Diverting money from each paycheck into a 401(k) plan is an example of dollar-cost averaging.

Why it matters: Dollar-cost averaging is a smart strategy in all market conditions, but especially during periods of market volatility. Since the set amount of money buys more shares when the stock price goes down and fewer shares when it rises, it evens out the average price you pay, ensuring you don't buy in bulk at high prices.

There's also the psychological benefit: Automatically deploying funds on a regular basis takes the emotion out of investing and helps investors resist the urge to try to guess which way the market will move.

Risk refers to the possibility that an investment will perform poorly or even cost you your initial investment. Generally speaking, a low-risk investment will deliver lower potential returns. The more risk you are willing to take on, the more potential upside there is — and the higher the likelihood that you could lose your shirt.

Why it matters: If you know you absolutely need the $100 in your pocket to pay for something next month, you want to stick the money in a conservative investment (cash or certificates of deposit) where the principal is guaranteed to be there when you need it.

The act of spreading your eggs across different baskets is how investors build a portfolio that doesn't turn into a scrambled, worthless mess on the way to the end goal. Generally, the baskets here are asset classes: stocks, bonds, mutual funds and cash.

Why it matters: Diversification is a way to reduce your exposure to risk. When one investment zigs, it's likely other investments in the portfolio will act differently (zagging) to smooth out returns.

The active strategy, like it sounds, involves hands-on money management, investing in and getting out of stocks based on the results of research and the market's fluctuations. Passive investing is the buy-and-hold approach, where investors purchase shares and hold onto the shares regardless of short-term price fluctuations.

Why it matters: Even if you don't invest in individual stocks, if you own mutual funds (within a workplace retirement plan or an IRA), you're exposed to either active or passive management. An actively managed mutual fund is headed by a person who chooses the investments in the fund. Index mutual funds are considered passive because the investment mix simply mirrors a particular section of the stock market.

Because passive funds aren't managed by a high-priced professional money manager, investors pay much lower management fees to own them, meaning more of their dollars get invested instead of eaten up by fees.