Want $1 Million in Retirement? 5 Simple Index Funds to Buy and Hold for Decades.

Achieving $1 million in retirement savings is no easy feat, but it is possible with enough time, consistent contributions, and the resolve to set aside money on a regular basis for investing.

Just as important as all of that is choosing the right place to put your money. Index funds are a great option because they offer you a wide array of investments. For example, if you want to invest in all sectors of the economy, you can choose a broad market fund. Or, if you prefer tech stocks, there are great funds for that, too.

Here's which index funds will help you get to $1 million and how much you'll need to invest over time to reach that goal.

Image source: Getty Images.

Five fantastic index funds you should consider

Vanguard is the standard in fund investing, not only because it offers a range of exchange-traded funds (ETFs), but also because it charges some of the lowest fees. For example, the Vanguard S&P 500 ETF (NYSEMKT: VOO) charges just 0.03% for its annual expense ratio -- compared to 0.41% for similar funds -- which means you'll pay as little as $3 in annual fees for every $10,000 invested.

Here are five Vanguard ETFs to consider buying, with each fund's dividend yield, returns over a five- and 10-year period, and returns since the fund's since inception:

Data source: Vanguard.

These funds will appeal to different types of investors, depending on how important dividends are to you, whether you want exposure to international stocks, or if you want to focus on a specific industry sector.

For example, the Vanguard Information Technology fund, as its name suggests, is invested in hundreds of U.S.-based technology companies. The fund is mostly focused on large-cap stocks, with its top 10 holdings accounting for 59% of its total assets. But it also has exposure to small-cap start-ups that have the potential to disrupt larger players.

Meanwhile, the Vanguard S&P 500 ETF follows the S&P 500 and gives you exposure to the 500 of the largest publicly traded U.S. companies. This fund is where I have the majority of my investments and it's a great option for investors who want to spread out their money across all sectors of the economy. Doing so helps ensure that if stocks in general are doing well, your portfolio will likely be doing well, too.

The other funds listed here are focused on growth stocks (Vanguard Growth), a total market index consisting of nearly all U.S. stocks (Vanguard Total Stock Market), and a broad basket of both U.S.-based and international stocks (Vanguard Total World Stock).

$1 million is achievable with the right plan

Now that we have a few index funds to consider, let's take a closer look at how to reach $1 million in retirement savings using them.

You probably noticed that the average annual returns varied across funds. To simplify our calculations, let's focus on the S&P 500's 10.5% historic average annual return since 1957.

No fund has a guaranteed return, and you could earn more or less in any given year. The 10.5% also doesn't account for inflation, but for our purposes, it's a good percentage to use because it represents the market's potential over decades of investing.

Calculations by author via Investor.gov.

As you can see, even with the historical average annual return of 10.5% and $10,000 invested annually (about $834 each month), it will take at least 25 years to reach $1 million. Of course, that figure will vary based on your returns and whether you invest more or less each year.

But the big takeaway here is that building sizable wealth takes time and patience. That's why putting money into an index fund as soon as possible and setting up automatic monthly investments is so important.

Automating your monthly contributions will help keep your retirement savings on track, and by selecting an index fund, you'll likely be less tempted to jump around from stock to stock or try to find the next big trend, and instead make steady gains toward your $1 million goal.

Chris Neiger has positions in Vanguard S&P 500 ETF. The Motley Fool has positions in and recommends Vanguard Growth ETF, Vanguard S&P 500 ETF, and Vanguard Total Stock Market ETF. The Motley Fool has a disclosure policy.