There's no safe and effective way to get rich in the stock market overnight, but with enough time, it's one of the best ways to generate wealth. The key, though, is to invest in the right places.

Investing in growth exchange-traded funds (ETFs) can be a smart way to maximize your earnings while still reducing risk. This type of investment is designed to earn higher-than-average returns. Each ETF contains dozens or even hundreds of stocks with the potential for above-average growth, making it more likely to beat the market over time.

ETFs, in general, can be a fantastic option for those looking for a low-maintenance investment. All of the stocks in the fund are already chosen for you, so you don't have to do as much research or upkeep as you would by investing in individual stocks.

Of course, there are never any guarantees when investing. But these three ETFs have a balance of risk and reward, and they could help you triple your money while barely lifting a finger.

1. Vanguard Growth ETF

The Vanguard Growth ETF (VUG -0.14%) is a powerhouse ETF containing over 200 growth stocks, just over half of which are from the tech sector.

It's also a large-cap growth ETF, which means all the stocks are from large companies. This can reduce your risk somewhat, because larger companies tend to be less volatile than their smaller counterparts. Around half of the fund's total composition is made up of the top 10 holdings, which are behemoth stocks like Amazon, Microsoft, Apple, Tesla, and Nvidia.

Historically, this ETF has been able to successfully beat the market over time. Over the past 10 years, it's earned total returns of nearly 238%, while the S&P 500 (^GSPC -0.00%) has earned total returns of around 160% in that time.

Another advantage of this fund is its rock-bottom expense ratio of just 0.04% per year. Some other funds have expense ratios of around 1% per year or more, and this ETF could potentially save you thousands of dollars in fees over time.

2. Schwab U.S. Large-Cap Growth ETF

The Schwab U.S. Large-Cap Growth ETF (SCHG 0.31%) is another growth ETF that only contains large-cap stocks. It includes 251 stocks, around 44% of which are from the tech industry. Because this ETF is slightly less focused on tech stocks than VUG, it can provide more diversification and lower your risk.

It's similar to VUG in some ways, including the fact that the top 10 holdings make up just over half of the fund's total composition. It also has an expense ratio of 0.04% per year, matching VUG's low fees.

That said, SCHG has earned higher returns than VUG. Over the past 10 years, it's earned total returns of roughly 270%, compared to VUG's 238% returns in that time.

3. Invesco QQQ Trust

Invesco QQQ Trust (QQQ 0.77%) is the highest performer on this list, but it also carries the most risk. It only contains 101 stocks, and a whopping 57% of the fund is allocated toward tech stocks. Of the three ETFs included here, then, QQQ is the least diversified. It also has the highest expense ratio at 0.20% per year.

However, it's also significantly outperformed both VUG and SCHG. Over the past 10 years, it's earned a total return of more than 367% per year -- more than double the S&P 500's performance over the last decade.

If you're thinking about investing in QQQ, consider your risk tolerance. There are no guarantees QQQ will keep up this type of performance over the long run, but if you're willing to take on more risk for the chance at earning higher returns, this could be the right fit for your portfolio.

Tripling your money over time

With enough time, it's possible to triple your money with next to no effort. Just keep in mind that growth ETFs can be incredibly volatile in the short term, and there's a chance they may not even beat the market at all. Before you buy, be sure you're willing to take on that level of risk.

^SPX Chart

^SPX data by YCharts

Over the past 10 years, VUG has earned an average annual return of roughly 14% per year. SCHG's 10-year average return is just under 15% per year, and QQQ has earned an average rate of return of around 17% per year in that time.

Again, there are no guarantees these ETFs will continue earning these types of returns. But if you were to invest, say, $2,000 in each of these funds while earning a 14%, 15%, or 17% average annual return, here's approximately how your savings would add up over time:

ETF Total Portfolio Value: 10 Years Total Portfolio Value: 20 Years Total Portfolio Value: 30 Years
VUG (14% avg. annual return) $7,000 $27,000 $102,000
SCHG (15% avg. annual return) $8,000 $33,000 $132,000
QQQ (17% avg. annual return) $10,000 $46,000 $222,000

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

To triple your money with these ETFs, you'd need to give your investments around 10 years to grow -- assuming they see similar returns in that time as they have over the past decade. If you're able to let your money sit longer (or invest an additional amount each month on top of your initial investment), you could potentially earn far more.

Investing in the stock market can be lucrative, and growth ETFs can help you make a lot of money over time. But it's important to consider your risk tolerance and keep in mind that no investment is a surefire bet. By investing wisely and keeping a long-term outlook, though, you could earn more than you might think.