You should be highly skeptical of any and all get-rich schemes ... except for the super-simple formula I'm going to show you below. Because this one really works.

It works so well that it's been used by the world's billionaires -- from the moguls of yesteryear, such as Rockefeller and Ford, to modern tycoons Carlos Slim and Warren Buffett.

The formula
It is, simply:

FV = PV * (1+r) ^ n

Where:

• FV = future value
• PV = present value
• r = rate of return
• n = time (or number of years)

Compounding 101
Now, some astute finance brains will recognize that equation not as some mystical secret, but as the "future value of money" (FVM) equation taught in college.

The FVM formula simply states that your future wealth (FV) is a function of three variables: the amount of money invested today (PV), the rate of return generated (r), and the length of time during which that money is put to work (n). As a result, maximizing future riches requires three steps.

Step 1: Increase PV
It takes money to make money. By actively and consistently slivering off a portion of your earnings every month to save and invest, you'll have more and more of that money working for you.

All things equal, the greater amount you invest today (PV), the greater wealth you'll build for tomorrow (FV).

Step 2: Increase r
Next, you'll need a way to grow that capital. Historically, the stock market has been the most effective wealth-building vehicle of all. Plowing your money into a low-cost index fund wouldn't be a bad idea.

But if you really want to maximize r, you'll need to allocate a portion of your portfolio to the best segment of the market over the past 50 years: small-cap value stocks. The reason is simple. Unlike behemoths such as \$180 billion AT&T (NYSE:T) and \$235 billion Microsoft (NASDAQ:MSFT) -- whose spectacular growth days are behind them -- reasonably priced small caps have tons of room to rocket. Take a look at Fama and French data, which tracked stocks from 1956 to 2005:

Segment

Value

Growth

Large caps

13.3%

9.7%

Small caps

17.3%

8.7%

Over the same time frame, the stock market as a whole returned 10.5%. All things equal, the greater your rate of return (r), the greater wealth you'll build for tomorrow (FV).

Step 3: Increase n
The last ingredient in our super-simple wealth-building recipe: maximum time in the market.

Look back at the equation. You'll see that n is an exponential function -- meaning that for every year you're not invested, you give up the awesome (almost magical) benefits of compounding.

All things equal, the longer you're invested (n), the greater wealth you'll build for tomorrow (FV).

Plug and chug
To get a feel for the three-step process in action, let's go back in time to see what kind of wealth would have been generated had someone:

1. Invested \$40,000 in the stock market.
2. Started 10 years ago.
3. Divided the money among five stocks having: market caps less than \$2 billion (to screen for small size), sales growth greater than 15% (to screen for above-average opportunities), and price-to-sales ratios of less than 2.0 (to screen for a fair price).

Here's what it would look like:

Company

Amount invested 10 years ago

Average compounded return over last 10 years

Total value of investment today

Barr Pharmaceuticals (NYSE:BRL)

\$8,000

22.1%

\$59,093

Helmerich & Payne (NYSE:HP)

\$8,000

24.3%

\$70,508

KHD Humboldt Wedag International (NYSE:KHD)

\$8,000

20.0%

\$48,167

Pride International (NYSE:PDE)

\$8,000

12.7%

\$26,445

II-VI (NASDAQ:IIVI)

\$8,000

29.7%

\$108,073

Total

\$40,000

22.8%

\$312,286

By having bought into five high-quality, reasonably priced companies while they were still babies, that \$40,000 stake would be worth more than \$300,000 today.

Of course, you can always fiddle with the numbers to generate different levels of FV, but our objective should remain the same:

1. Maximize PV by sticking to an investment plan.
2. Maximize r by devoting a chunk of your portfolio to superior small caps at attractive prices.
3. Maximize n by investing as soon as possible and for as long as possible.

The final Foolish variable
So don't waste another "n." Start plugging whopping returns into your own real-life wealth equation today.

If you need a few small-cap ideas to start you off, our specialists at Motley Fool Hidden Gems can help. Advisors Bill Mann and Seth Jayson make sure subscribers get the absolute most from the FVM formula. Since the newsletter's inception in 2003, its picks are up an average of 21%, versus 2% for like amounts invested in the S&P 500. You can see their five favorite small caps for new money with a free, 30-day trial. To learn more, click here.

This article was first published Oct. 12, 2007. It has been updated.

Fool contributor Brian Pacampara tried to get rich quick once, but his idea for a cold-air balloon never got off the ground. He owns no position in any of the companies mentioned. Microsoft is a Motley Fool Inside Value recommendation. II-VI is a Hidden Gems pick. KHD Humboldt Wedag is a Global Gainsselection. The Fool owns shares of KHD Humboldt Wedag. The Fool has a mathematical disclosure policy.