The price-to-earnings ratio (PE) is a popular measure of company values. It is a mathematical calculation that takes a company’s share price and divides this by the company’s earnings.
In simple terms, the PE ratio is a payback calculation that measures how many years it would take, in company earnings, to recoup the price paid for a particular share in that company. The lower the PE ratio the cheaper the share is in theory. The higher the PE ratio the more expensive the share is in theory.