Investing for retirement should be a priority for anyone with the means. Any amount is a good thing, but considering how much you'll likely need to not worry about outliving your savings, strictly saving won't do the job. You need to grow your money by investing.

With just a few exchange-traded funds (ETFs) that cover a lot of ground, you can have a solid foundation for your retirement portfolio. Try these two if you want the chance to supercharge your retirement savings.

1. iShares Core S&P 500 ETF

The iShares Core S&P 500 ETF (IVV -0.65%) mirrors the S&P 500, which tracks the largest 500 public U.S. companies by market cap. The S&P 500 is the stock market's most popular index because its performance is generally used to gauge the stock market's health.

The iShares Core S&P 500 ETF instantly checks a lot of important boxes. It contains companies from all major sectors, so there's instant diversification (although only large-cap companies), every blue chip stock is included, the historical performance is there, and it's extremely low cost with a 0.03% expense ratio.

Of those, the low-cost part may be the most overlooked, likely because the difference between expense ratios on paper seems small enough not to warrant serious thought. After all, the differences can be fractions of 1%, depending on the ETFs. Seemingly nothing. However, through the course of a career while you're investing for retirement, these small differences in fees can really add up.

Let's imagine a scenario where you invest $1,000 monthly into funds that average 10% annual returns over 30 years (the rough historical average of the S&P 500). Here's how your investments would stack up with different expense ratios:

Expense Ratio Investment Value Amount Paid in Fees
0.03% $1.962 million $11,177
0.30% $1.865 million $108,761
0.60% $1.762 million $211,104

Data source: Author's calculations.

Having an extremely low-cost option can save you lots of money throughout your career. With low costs, you can't go wrong with the iShares Core S&P 500 ETF. Fees matter -- don't overlook them.

2. The Vanguard Total International Stock ETF

A good rule of thumb is to have around 20% of your stock portfolio in international stocks. Considering how many great companies and opportunities exist across the globe, you'd be doing yourself a disservice to only invest in U.S. companies. It also gives you a chance to hedge against the U.S. economy a bit, so your portfolio isn't fully dependent on economic conditions here.

The Vanguard Total International Stock ETF (VXUS -0.67%) is a good choice because it contains stocks from both developed markets and emerging markets.

In general, developed markets are regions with more advanced economics, better infrastructure, and established industries. Examples include the U.K., Japan, and Australia. Emerging markets don't quite have the infrastructure and economic stability of developed markets, but they're viewed as progressing that way. Examples are Brazil, China, and Mexico.

Investing in both markets gives you access to the relative stability that comes with developed markets, and the upside that comes with emerging markets because of their growth potential. Here's how the ETF is broken down by region:

  • Emerging markets: 25.3%
  • Europe: 40.1%
  • Pacific: 26.7%
  • North America: 7.4%
  • Middle East: 0.5%

Unlike the S&P 500, which only includes large-cap companies, this ETF contains over 7,900 small-cap, mid-cap, and large-cap companies. The top 10 holdings also only account for just over 9% of the fund, compared to Apple and Microsoft accounting for over 12% of the S&P 500 by themselves. The Vanguard Total International Stock ETF is as diversified as it comes.