The end of the year is the perfect opportunity to double-check your portfolio and make sure all your investments deserve to be there. It's also a smart time to add new investments and start the new year off with a bang.

With countless stocks and funds to choose from, though, it can sometimes be overwhelming to pick the right one.

There's one exchange-traded fund (ETF), however, that's lower-risk and also packs a punch: the Vanguard S&P 500 ETF (VOO 0.49%). Not only does this ETF make a smart long-term investment, but by investing now, you could also potentially double your money in 2022.

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Why invest in an S&P 500 ETF?

The Vanguard S&P 500 ETF aims to mirror the performance of the S&P 500 index itself. It contains stocks from the same 500 companies, and it's designed to earn roughly the same returns as the index.

This ETF has several advantages, too. For one, it's very likely to survive stock market turbulence. The S&P 500 itself does experience short-term volatility, but it's always recovered from every downturn it's ever faced.

Nobody knows for certain if a market crash is looming, but some experts believe we'll see a downturn in 2022. If that happens, an S&P 500 ETF can be a smart investment to have in your portfolio. Although it may take a hit in the short term, it's almost guaranteed to bounce back eventually.

The Vanguard S&P 500 ETF is also a powerhouse investment that can help your savings grow relatively quickly. Historically, the S&P 500 has earned an average annual return of around 10% per year. Some years you may earn less than that, while other years (such as 2020 and 2021), you could earn significantly higher returns.

How to double your money in 2022

When investing in the stock market, time is your most valuable resource. One of the best ways to increase your savings is to invest consistently and give your money as much time as possible to grow.

Say you invest $1,000 in the Vanguard S&P 500 ETF on January 1, 2022. Let's also say you continue investing $100 per month, and you're earning a 10% average annual rate of return. By the end of the year, you'll have a total of around $2,300.

Of course, nothing is guaranteed when it comes to the stock market. If 2022 is a rough year for the market, you may earn lower returns. Over the long run, though, you're likely to see positive returns and accumulate a substantial amount of money as long as you continue investing regularly.

For instance, say that you continue investing $100 per month in the Vanguard S&P 500 ETF. After 10 years, you'll have close to $28,000, assuming you're still earning a 10% average annual return. In 30 years, you'll have accumulated around $215,000.

Investing in the stock market can be a fantastic way to generate wealth, and the Vanguard S&P 500 ETF is a strong choice for many reasons. Regardless of where you invest, getting started now and investing consistently can make it easier to make money in the stock market.