PE Ratio of a company is a basic tool to check the quality of a stock .
Its formula is market price / earnings per share .
no
f shares / total profit = earnings per share .
Say a PE of 2 , it means ideally the company would earn the money invested in 2 years and the rest is profit . PE of 5 would mean , you would earn the money in 5 years and PE of 20 means you earn in 20 years and so on . Some fast growing companies demand higher PE because of the growth expectation in the stock .
Generally the lower the PE , the cheaper the stock is provided the company is expected to keep making profits at the same or better levels .
Hope you understand .