Home›Glossary›P/E Ratio

P/E Ratio

Investment

Price-to-Earnings Ratio

A stock valuation metric that compares a company's current share price to its earnings per share. It indicates how much investors are willing to pay for each rupee of earnings — a high P/E suggests high growth expectations.

Definition

The Price-to-Earnings (P/E) ratio is the most widely used stock valuation metric. It compares a company's current share price to its earnings per share (EPS), indicating how much investors are willing to pay for each rupee of the company's earnings.

A high P/E suggests investors expect strong future earnings growth (or the stock is overvalued). A low P/E suggests modest growth expectations, undervaluation, or potential fundamental problems.

P/E is most meaningful when compared against: the company's own historical P/E, the sector average P/E, and the broad market (Nifty 50) P/E. Comparing P/E across different sectors is misleading — a high P/E for a software company is normal; the same P/E for a bank would be exceptional.

Formula

P/E Ratio = Market Price per Share / Earnings per Share (EPS)

EPS = Net Profit / Total Shares Outstanding

Equivalently at the company level: P/E = Market Capitalisation / Net Profit

Worked Example

Infosys (hypothetical data):

  • Current share price: ₹1,800
  • EPS (last 12 months): ₹72

P/E = ₹1,800 / ₹72 = 25×

This means investors are paying ₹25 for every ₹1 of Infosys's annual earnings. The IT sector average P/E is 30×, so Infosys appears slightly below sector average — potentially attractive relative to peers.

Compare with a PSU bank trading at:

  • Share price: ₹180
  • EPS: ₹30
  • P/E = 6×

The bank appears far cheaper, but banking businesses typically trade at lower P/E due to capital intensity, regulatory constraints, and credit risk — the comparison only makes sense within the banking sector.

Key Things to Know

  • P/E and growth (PEG ratio): A high P/E is justified if earnings are growing rapidly. The PEG (Price/Earnings to Growth) ratio = P/E ÷ Annual EPS Growth Rate. A PEG below 1 is generally considered undervalued (paying less than 1× for each percentage point of growth). PEG normalises P/E for growth.
  • Cyclical businesses: For cyclical industries (auto, steel, real estate, commodities), P/E is notoriously unreliable. In boom years, profits are high → P/E looks low (but the company is actually at peak). In down years, profits collapse → P/E looks high (but the company may be near the bottom). For cyclicals, use EV/EBITDA or Price-to-Book instead.
  • Nifty 50 P/E as market thermometer: NSE publishes the Nifty 50 P/E daily. Historically: Nifty P/E below 16 = market is cheap (strong long-term entry point); 16–22 = fair value; above 22 = expensive (exercise caution). This is a rough guide, not a precise timing tool.
  • Earnings quality matters: Two companies can have the same P/E but very different earnings quality. Look for companies with consistent, cash-backed earnings. Companies with high EBITDA but low net profit due to heavy depreciation or finance costs may deserve a lower P/E than their EPS-based ratio suggests.
  • P/E vs CAGR: If a company's earnings are growing at 20% CAGR and the P/E is 20×, you are paying 1× PEG — reasonable. If earnings are growing at 5% CAGR and P/E is 30×, you are paying 6× PEG — expensive. Connecting P/E to earnings CAGR gives a more complete picture than P/E alone.

Related Calculators

ROI Calculator →Calculate your return on investment (ROI), annualized return, and net profit. Works for stocks, mutual funds, real estate, and any investment in India.
CAGR Calculator →Calculate the Compound Annual Growth Rate of any investment instantly. Enter your initial value, final value, and time period to find CAGR or projected returns.

Related Terms

EBITDAEarnings Before Interest, Taxes, Depreciation and AmortisationROIReturn on InvestmentCAGRCompound Annual Growth RateDividend YieldAnnual Dividend Yield
Frequently Asked Questions
What is a good P/E ratio for Indian stocks?
There is no universal 'good' P/E — it must be compared within the same sector and relative to historical averages. The Nifty 50 has historically traded between 15–25× P/E. Below 15 is generally considered cheap; above 25 suggests expensive or high-growth expectations. Sectors like FMCG and IT typically trade at 30–50× P/E; banking at 8–15×.
What is the difference between trailing P/E and forward P/E?
Trailing P/E (TTM P/E) uses earnings from the past 12 months — it is based on actual, reported results. Forward P/E uses analyst estimates of earnings for the next 12 months — it reflects expected future performance. Forward P/E is more useful for fast-growing companies where past earnings underrepresent the future; trailing P/E is more reliable since it uses actual data.
Can P/E be negative?
Yes. If a company reports a net loss (negative EPS), the P/E ratio is negative or undefined. Negative P/E ratios are meaningless for valuation purposes. For loss-making companies, analysts use other metrics like Price-to-Sales (P/S), EV/EBITDA, or Price-to-Book (P/B) instead.
How is the Nifty 50 P/E used to assess market valuation?
The Nifty 50 P/E (published daily by NSE) is a broad market valuation indicator. Historically, markets have offered good long-term returns when bought at P/E below 20, and lower returns when bought at P/E above 25. However, P/E alone is not a market timing tool — many investors use it as one of several signals, not as a standalone buy/sell trigger.
Is a low P/E always a good buying opportunity?
Not always. A low P/E may reflect genuine undervaluation (a buying opportunity) or a 'value trap' — a company with declining earnings, structural problems, or a deteriorating business where earnings are likely to fall further, making the stock actually expensive relative to future earnings. Always analyse why the P/E is low before investing.