The price-to-earnings ratio (P/E) is one of the most quoted numbers in the stock market. It tells you how much investors are paying for every rupee or dollar of a company's yearly profit. This article explains how P/E is calculated, what a high or low figure can mean, why comparing P/E across very different companies misleads, and where P/E stops being useful.
What P/E means
P/E compares a company's share price with its earnings per share (EPS), the profit attributable to each share over the last year. A P/E of 20 means investors are paying ₹20 (or $20) for every ₹1 (or $1) of yearly profit.
Formula: P/E = share price ÷ earnings per share. The same figure can be calculated as market capitalisation ÷ total yearly profit.
Another way to read P/E: if a company's profit stayed exactly the same every year, a P/E of 20 would mean about 20 years of profit to equal what you pay for the share today. Of course, profits rarely stay the same, which is why P/E is a starting point, not a verdict.
A simple example
A company's share trades at ₹500, and it earned ₹25 per share over the last year. Its P/E is 500 ÷ 25 = 20. Another company's share trades at ₹200 and earned ₹20 per share, so its P/E is 10. The second share has a lower price and a lower P/E, but the share price alone tells you nothing; it is the price compared with profit that matters.
Why P/E differs between companies
Expected growth: investors usually pay more for each rupee of profit when they expect profits to grow fast. That is why fast-growing companies often have high P/E ratios and slow-growing ones lower figures.
Stability: companies with steady, predictable profits, such as many consumer brands, often trade at higher P/E ratios than companies whose profits swing with the economy or commodity prices.
Sector: different industries have very different typical P/E levels. Comparing a bank's P/E with a software company's says little; comparing a company with others in its own sector says more.
Interest rates: when interest rates are low, investors are often willing to pay higher P/E ratios across the market, and vice versa.
Example on PositoAI: P/E across India
On 20 Oct 2026, P/E ratios on PositoAI ranged widely among well-known Indian companies: ONGC about 6.5, State Bank of India about 10.4, TCS about 17.3, Reliance Industries about 21.8, Hindustan Unilever about 41.6 and Asian Paints about 46.9.
Of 2,140 ranked Indian companies, 559 had a P/E under 15, 598 between 15 and 30, 454 between 30 and 60 and 280 above 60, while 249 had no meaningful P/E because they made a loss. (Figures as on 20 Oct 2026; they change daily.)
Example on PositoAI: P/E in the United States
In the US, JPMorgan Chase traded at a P/E of about 14.0, Microsoft about 29.7 and Apple about 39.3, while Tesla was about 340.8, a sign of how much future growth investors were paying for. Ford, which made a loss in its latest year, had no meaningful P/E. Of 4,001 ranked US companies, 1,757 had no meaningful P/E because of losses, a far larger share than in India, mostly smaller companies. (As on 20 Oct 2026.)
Trailing and forward P/E
Trailing P/E uses the profit of the last 12 months, which is known and reported. Forward P/E uses analysts' estimates of next year's profit, which may or may not come true. PositoAI's P/E is a trailing figure, based on reported profit.
Where P/E stops being useful
Losses: when a company makes a loss, P/E is negative or blank and not meaningful.
One-time items: a large one-time gain (such as selling a business) can make profit look unusually high and P/E unusually low for a year, and a one-time loss can do the opposite.
Cyclical companies: in sectors such as steel, metals and commodities, profits peak at the top of the cycle, so P/E can look lowest exactly when profits are about to fall.
Very low P/E is not automatically cheap; it can reflect real problems or expected declines.
Common misconceptions
"A low P/E means a stock is cheap." It can also mean the market expects profits to fall.
"A high P/E means a stock is expensive." It can reflect strong expected growth, though high expectations also carry risk if they are not met.
"P/E can be compared across any companies." It is most useful within the same sector.
Frequently asked questions
What is a good P/E ratio?
There is no single good figure; it depends on the sector, growth and interest rates.
Why do some companies show no P/E?
Because they made a loss, so the ratio is not meaningful.
What is EPS?
Earnings per share: a company's yearly profit divided by its number of shares.
Is P/E enough to judge a company?
No. It works best alongside growth, debt, cash flow and other measures.
How to use this on PositoAI
Every company's PosiFunda page shows its P/E compared with similar companies, under Standard fundamentals, alongside PosiFunda Ratios such as Profit Cash and Growth Efficiency that show the quality behind the profit. The Low PE Top 10 lists rank profit-making companies by P/E. PosiStep 14 of PosiCourse, PositoAI's free stock market course, explains the key ratios.
Suggested reading
What Is the P/B Ratio? · How to Read Quarterly Results · How to Understand Company Debt · What is Market Capitalization? · What is Fundamental Analysis?
Summary
P/E is the share price divided by earnings per share: how much investors pay for each unit of yearly profit. It differs with expected growth, stability, sector and interest rates, so it is most useful when comparing similar companies. P/E is not meaningful for loss-makers, can be distorted by one-time items, and can mislead for cyclical companies. A low P/E is not automatically cheap and a high one is not automatically expensive.