how to work out or site for p/e ratio

  1. 417 Posts.
    G'day. I've got a formula i use constantly to determine if i should buy or not. One vital part of that formula is the P/E ratio. I have been going to 3 different sites, and all 3 have different price/earning figures, which totally blows my formula. Does anyone have an accurate site to go to, that's live, and/or know the formula to work it out manually.

    Much appreciated.
 
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