The Price/Earnings ratio, or P/E Ratio, is a fraction with the share price in the numerator and the earnings (profit)/share in the denominator.
Consider a company with one million total shares and profits of $100 million. Their stock price trades at $1,600/share. Thus the P/E Ratio will be $1,600/(100,000,000/1,000,000)= 16. 16 is considered a standard P/E Ratio. Early stage growth stocks tend to have higher P/E ratios and mature companies tend to have lower P/E ratios.