Investors like exchange-traded funds because it's easy for them to get diversified exposure to the investments they want in a single package. Although you can find focused ETFs that narrow down on a thin slice of the market, some investors just want to make things as simple as possible and get a single ETF that gives them as much of the market as possible.

Total market ETFs aim to give investors the maximum possible diversification in one fund. Among the best such funds, you'll find Schwab U.S. Broad Market (NYSEMKT:SCHB), iShares Core S&P Total U.S. Stock Market (NYSEMKT:ITOT), and Vanguard Total World Stock (NYSEMKT:VT). Let's look more closely at these total market ETFs to see which one best fits your needs.

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Total Market ETF

Assets Under Management

Expense Ratio

1-Year Return

Schwab U.S. Broad Market

$12 billion

0.03%

21%

iShares Core S&P Total U.S. Stock Market

$13.2 billion

0.03%

21%

Vanguard Total World Stock

$10.6 billion

0.11%

24%

Data source: Fund providers, ETFdb.com.

2 ways to get the whole U.S. stock market

Total stock market ETFs that cover the U.S. stock market are fairly common, but the Schwab and iShares funds above are among the best in terms of low costs. With an expense ratio of 0.03%, you'll pay just $3 annually for every $10,000 you invest in either fund.

The two ETFs take slightly different tacks toward getting their exposure. The Schwab fund tracks the Dow Jones U.S. Broad Stock Market Index, which tries to track the performance of large-cap and small-cap domestic stocks by selecting a substantial subset of the entire U.S. stock universe. In particular, the index includes the 750 stocks that meet Dow Jones' qualifications for large-cap stocks in its primary index, and the 1,750 stocks that get assigned to the corresponding small-cap stock benchmark. The annual composition of the index is determined each September, which can lead to changes in the index holdings and therefore spur Schwab to make shifts in its ETF portfolio.

The iShares ETF tracks the S&P Total Market Index, a benchmark with an even broader scope. The methodology for the index says that it includes all eligible U.S. common stocks, which currently includes almost 3,800 large-cap, mid-cap, small-cap, and micro-cap stocks. Market caps range from nearly $900 billion to just over $1.33 million, giving investors a broader span of the stock universe than the Schwab ETF. Yet because the fund is weighted by market capitalization, the differences in performance between the two funds have been relatively small over time, and that makes either one a good choice for those seeking domestic stock exposure.

All the stocks in the world

If the U.S. isn't enough for you as an investor, though, you'll want a global alternative. The Vanguard ETF offers true worldwide total stock market coverage, as it tracks the FTSE Global All Cap Index of stocks. The fund holds nearly 8,000 stocks that span the globe, including both U.S. and foreign companies. North America represents about 55% of the portfolio, but developed countries in Europe and the Pacific region represent 35% of assets, and emerging markets make up the remaining 10%.

You can see from the performance above that the addition of international stocks helped boost returns in 2017 compared to how U.S.-only total market ETFs did. That won't always be the case, as international stocks sometimes underperform the U.S. market. Expenses are also slightly higher, reflecting the increased costs of dealing in international stock markets. Nevertheless, if you value international exposure, the Vanguard fund offers a true all-world experience.

Get what you need

Many investors like having lots of different investments, but the simplicity of having extensive stock exposure in a single ETF appeals to those who don't like to clutter up their portfolios unnecessary. By using these ETFs, you can get the total market coverage you want without paying more than you should to get it.

Dan Caplinger has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.