It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Let's take a look at some of our top-ranked mutual funds with the lowest fees.

Vanguard PRIMECAP Fund Investor (VPMCX) has a 0.35% expense ratio and 0.34% management fee. VPMCX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. With yearly returns of 15.08% over the last five years, this fund clearly wins.

MFS Blended Research Value Equit R6 (BRUNX): 0.35% expense ratio and 0.25% management fee. BRUNX is a part of the Large Cap Value category, and invests in equities with a market capitalization of $10 billion or more, but whose share prices do not reflect their intrinsic value. BRUNX, with annual returns of 13.02% over the last five years, is a well-diversified fund with a long track record of success.

American Century International Value I (ACVUX Quick QuoteACVUX - Free Report) : 0.94% expense ratio and 0.9% management fee. ACVUX is a part of the Non US - Equity fund category, many of which will focus across all cap levels, and will typically allocate their investments between emerging and developed markets. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 13.08% over the last five years.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.