EPS = Net Profit ÷ Total number of shares. If a company earns ₹1,000 crore and has 100 crore shares outstanding, EPS is ₹10.
EPS is more useful than raw profit because it accounts for the company issuing new shares. If profit grows 20% but the company issues 20% more shares, EPS may not grow at all.
You'll see EPS quoted a lot because it's the E in the PE ratio.
What to watch: EPS growing steadily over 3-5 years is a healthier sign than one bumper year.