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.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term investors' portfolios.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

If you are looking to diversify your portfolio, consider Nuveen Multi-Cap Value I (NQVRX). NQVRX is a Large Cap Value fund. These funds invest in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. This fund is a winner, boasting an expense ratio of 0.82%, management fee of 0.69%, and a five-year annualized return track record of 13.26%.

T. Rowe Price US Large-Cap Core I (RCLIX): 0.57% expense ratio and 0.53% management fee. RCLIX is a part of the Large Cap Growth mutual fund category, which invest in many large U.S. companies that are expected to grow much faster compared to other large-cap stocks. RCLIX, with annual returns of 11.59% over the last five years, is a well-diversified fund with a long track record of success.

Carillon Clarivest Intl Stock R6 (EISVX Quick QuoteEISVX - Free Report) is an attractive large-cap allocation. EISVX 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. EISVX has an expense ratio of 0.85%, management fee of 0.7%, and annual returns of 15.13% over the past 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.