Price-earnings ratios of ETFs are easy to find

— -- Q: How can I get the price-to-earnings ratio of an exchange-traded fund (ETF)?

A: Some investors use price-to-earnings ratios (P-Es) to determine how cheap or expensive a stock is.

The P-E ratio is the price of a stock divided by its earnings. You can either divide by past earnings, to get the trailing P-E, or future expected earnings, to get the forward P-E. The higher the P-E, the more investors are paying for each dollar in earnings the company is generating.

You can do the same analysis for exchange-traded funds. You can get the P-E of an ETF from:

•The provider of the underlying index. ETFs are investments that own the stocks in an index. That means if you can get the P-E of the index, you know the P-E of the ETF. Some popular indexes provide their P-E ratios. Say you're invested in an ETF that tracks the Standard & Poor's 500 index. You can get the P-E of the S&P 500 here.

•The ETF sponsor. Some of the major ETF providers allow investors to look up the average P-E of the stocks owned by an ETF. iShares has an excellent site to help you with this. Let's say you own the iShares Russell 1000 Value Index iwd. Look up the fund at iShares.com and you will see a screen that gives full details about the ETF. Scroll down and you'll see "Price/Earnings" listed under "Fundamentals."

•Morningstar. Log onto www.morningstar.com and enter the ETF's ticker symbol. Next, click on the "portfolio" option on the left-hand side of the screen. Scroll down and you'll see the ETF's "price/prospective earnings" and how it compares to the S&P 500.

Matt Krantz is a financial markets reporter at USA TODAY. He answers a different reader question every weekday in his Ask Matt column at money.usatoday.com. To submit a question, e-mail Matt at mkrantz@usatoday.com.