LONDON -- It's always worth keeping an eye on the earnings forecasts for your favorite companies, especially if you use forward P/E ratios to gauge when to buy and sell your shares. You never know; if City brokers have been revising their projections of late, your investments may not be as cheap -- or expensive -- as you think!

Today I'm looking at the earnings-per-share forecasts for BHP Billiton (LSE: BLT.L) (NYSE: BBL), the FTSE 100 diversified miner. All my figures are courtesy of S&P Capital IQ.

The consensus for 2013 is for EPS of 170 pence, which puts the 1,926 pence shares on a forward P/E of 11. The estimates suggest earnings may rise to 196 pence per share for 2014 and climb to 202 pence for 2015. EPS may then rise further to 206 pence for 2016 before falling back to 198 pence in 2017, at least according to City analysts.

The data from S&P Capital IQ also indicates BHP Billiton's revenue may rise from 43 billion pounds in 2013 to 48 billion pounds the following year before climbing to 52 billion pounds the year after. However, apart from rising revenue, the forecasts for BHP aren't great: Profits are essentially predicted to go nowhere between 2014 and 2016. But then again, that P/E of around 11 suggests the market is already expecting that earnings won't advance anytime soon.

Whether these projections make BHP Billiton a buy, a hold, or a sell is, of course, up to you. To put the company's multiple into perspective, the FTSE 100 at 5,755 trades on a P/E of 11.4.

As well as BHP Billiton, there are plenty of great FTSE stocks out there. Some of them are listed in our special in-depth Motley Fool report "Eight Top Blue Chips Held By Britain's Super Investor." The report is completely free and shows where buy-and-hold maestro Neil Woodford believes the best FTSE shares are to be found today. You can download the report here.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.