Investing in the stock market is one of the best ways to generate long-term wealth, but you don't need to be rich to get started. In fact, contributing even a couple hundred dollars per month can add up to $1 million or more over time.

However, where you invest will make all the difference in how much you're able to earn. Exchange-traded funds (ETFs) require next to no effort on your part, and they can minimize risk while helping turn everyday savings into life-changing wealth. And there's one ETF, in particular, that could turn $200 per month into $1 million.

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A growth ETF that packs a punch

An ETF is a collection of stocks bundled together into a single investment. When you buy just one share of an ETF, you'll gain exposure to every stock included in that fund. Some funds contain a few dozens stocks from one industry, while others may include hundreds or even thousands of stocks across all sectors of the market.

If you're looking to earn above-average returns with minimal effort, the Vanguard Growth ETF (VUG -0.79%) may be a smart choice. This fund tracks the CRSP U.S. Large-Cap Growth Index, and it contains 166 stocks from all 11 market sectors.

A key advantage of this ETF is its balance of risk and reward. It only contains large-cap stocks, which are companies with a market capitalization of at least $10 billion. A few of the largest holdings -- such as Apple, Microsoft, and Nvidia -- are also considered megacap stocks with a market cap of more than $200 billion.

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Large- and megacap stocks can carry less risk than smaller companies, as they're industry-leading behemoths that are more likely to survive periods of market turbulence. At the same time, though, this fund only contains stocks with the potential for above-average growth -- making it easier to build substantial wealth over time.

Turning $200 per month into more than $1 million

It's important to note that nobody knows exactly how stocks will perform going forward, especially in the coming weeks or months. But historically, the market itself has earned an average annual rate of return of around 10%, meaning all the annual highs and lows have averaged out to roughly 10% per year.

Over the last decade, the Vanguard Growth ETF has earned an average rate of return of 15.29% per year, while its average return since its inception in 2004 is 11.51% per year.

For simplicity's sake, let's assume that this fund earns an average return of 12% per year going forward. If you were to invest $200 per month at that rate, here's approximately how much you could accumulate depending on how many years you let your money grow:

Number of Years Total Portfolio Value
20 $173,000
25 $320,000
30 $579,000
35 $1,036,000

Data source: Author's calculations via investor.gov.

In this scenario, it would take around 35 years of consistent investing to turn $200 per month into at least $1 million. However, you could reach that goal sooner with slightly higher monthly contributions or a higher average annual return.

For example, if you begin contributing $400 per month, all other factors remaining the same, you could reach $1 million around six years sooner. Similarly, if this fund were to earn a 15% average annual return, as it has over the past decade, you could earn $1 million in around 30 years with just $200 per month or 25 years with $400 per month.

No matter how much you're investing or what kind of returns you're earning, getting started now is one of the most important factors in building wealth. By investing consistently for as many years as possible, you could earn more than you might think with the Vanguard Growth ETF.