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P/E Ratio

A company’s share price divided by its earnings per share.

Also called: price to earnings · price earnings ratio · pe

In plain language

The P/E ratio expresses how many dollars investors pay for each dollar of annual earnings. A P/E of 25 means $25 of price per $1 of earnings.

Trailing P/E uses the last twelve months of reported earnings; forward P/E uses analyst estimates, which are forecasts and are often wrong.

A high P/E is not automatically expensive and a low one is not automatically cheap. Fast-growing companies routinely carry high multiples, and low multiples often reflect real problems.

The formula

P/E Ratio

Share Price ÷ Earnings Per Share

Why it matters

P/E is context, not a signal. It tells you what expectations are priced in, which helps explain why a stock can fall on good news.

Common mistakes

  • Comparing P/E ratios across industries with completely different growth profiles.
  • Using P/E on companies with negative or barely positive earnings, where it is meaningless.
  • Treating a low P/E as a trade signal on its own.

Keep exploring

These concepts are connected. Understanding one usually makes the next one easier.