The PE ratio compares a company’s share price with its earnings per share, so it shows how many rupees investors pay for every rupee of yearly profit. A PE ratio of 15 means the stock trades at 15 times its earnings. This guide covers the formula, trailing and forward versions, a worked example and the limits you should know.
Key Takeaways
- PE ratio = market price per share divided by earnings per share (EPS).
- Trailing PE uses the last 12 months of profit, while forward PE uses an estimate of future profit.
- There is no single good PE ratio. Compare it with the company’s own history, its sector peers and its growth.
- One-time gains, share dilution and cyclical profits can make a PE ratio look better or worse than the real picture.
- Earnings yield, which is EPS divided by price, is the PE ratio turned upside down and helps compare stocks with bank rates.
In this article
- What is the PE ratio?
- PE ratio formula and how to calculate it
- Types of PE ratio
- How to read the multiple against growth and peers
- Worked example with numbers
- When it works and when it misleads
- Where to check earnings and price data
- Pros and cons
- Checklist and common mistakes
- Frequently asked questions
- The bottom line
What Is the PE Ratio?
PE ratio stands for price to earnings ratio. You will also see it written as P/E or PE multiple. It divides the market price of one share by the earnings per share (EPS) the company reported. EPS is the profit that belongs to ordinary shareholders, divided by the number of shares.
Think of it as a payback clock. If a company earns ₹20 per share each year and the share costs ₹300, you pay 15 times one year of earnings. If profit stayed flat, it would take 15 years of profit to cover the price.
Index providers publish the same measure for whole baskets of stocks. The Nifty 50 factsheet on the NSE Indices website lists P/E, P/B and dividend yield under a Fundamentals heading, so you can see the figure for the index as well as for single companies.
Where the inputs come from
Both inputs are public. The share price comes from the exchange. EPS comes from the profit and loss statement in the quarterly results or the annual report. Companies report basic EPS and diluted EPS, and large groups report both standalone and consolidated figures. Use the same basis every time, or your comparison will mislead you.
PE Ratio Formula and How to Calculate It
The PE ratio formula has one main form and one shortcut:
- Per share: PE ratio = market price per share ÷ earnings per share (EPS).
- Whole company: PE ratio = market capitalisation ÷ net profit after tax attributable to shareholders.
Both give the same answer, because the share count cancels out.
Two ways to calculate the PE ratio
Use the per-share method with a quote screen and the whole-company method with the results filing. If the two answers differ, the share count or profit figure is mismatched.
Finding EPS for the PE ratio
- Open the latest profit and loss statement and note net profit attributable to equity shareholders.
- Add up the last four quarters if you want the trailing twelve months figure.
- Find the weighted average number of equity shares for the same period.
- Divide profit by shares to get EPS, then divide the current share price by EPS.
Types of PE Ratio: Trailing, Forward and Sector
Not every PE ratio on a website is built the same way, so know which version you are looking at.
Trailing PE
Trailing PE uses profit from the last four reported quarters. It is based on facts that have already happened, which makes it the most common version on screeners. Its weakness is that it looks backwards, so a company whose profit is about to jump looks expensive.
Forward PE
Forward PE uses an estimate of next year’s EPS. It looks ahead, but the estimate may come from analysts or from management guidance, and both can be wrong. Always ask who made the forecast. Never mix a trailing figure for one company with a forward figure for another.
Sector and index PE
Sector PE is the combined price over the combined earnings of companies in one sector. Index PE does the same for an index. These show whether a stock is expensive against its own group. Banks, software firms and steel makers trade at very different multiples, so a sector comparison is fairer.
How to Read the Multiple Against Growth and Peers
A low number is not automatically a bargain and a high number is not automatically a warning. The market pays more for earnings it expects to grow, so ask why the multiple sits where it does.
Low PE. It can mean the stock is out of favour, that profits are at a cyclical peak, or that investors doubt the quality of earnings. Check each of these before calling it cheap.
Moderate PE. Many stable businesses with steady growth trade here, though the normal range differs by sector. Compare with peers, not with the whole market.
High PE. The market may expect fast growth, strong returns on capital or a scarce business model. A high multiple is only fair if the growth arrives.
Reading the PE ratio with PEG and earnings yield
Two quick tools help. The PEG ratio divides the PE ratio by the expected annual profit growth rate in percent. A PE of 15 with 12% growth gives a PEG of 1.25. The earnings yield is EPS divided by price, which for the same stock is 20 ÷ 300, or about 6.67%. Earnings yield lets you compare a stock with deposit and bond rates. Our guide to the PB ratio explains how price to book links to earnings through return on equity.
PE Ratio Worked Example With Numbers
Suppose a company, Beta Foods Ltd, reports the following. Every figure here is hypothetical and used only to teach the method.
Step-by-step calculation
- Net profit for the last four quarters is ₹60 crore and there are 3 crore shares, so EPS = 60 ÷ 3 = ₹20.
- The share trades at ₹300, so PE ratio = 300 ÷ 20 = 15.
- Cross-check: market capitalisation = 300 × 3 = ₹900 crore, and 900 ÷ 60 = 15. Both methods match.
- Forward view: analysts expect next year’s profit of ₹72 crore, so forward EPS = 72 ÷ 3 = ₹24 and forward PE = 300 ÷ 24 = 12.5.
- Earnings yield = 20 ÷ 300 = 6.67%, and the PEG at 12% growth = 15 ÷ 12 = 1.25.
| Company | Price | EPS | PE ratio | What it says |
|---|---|---|---|---|
| Beta Foods | ₹300 | ₹20 | 15 | Mid-range multiple in this example |
| Gamma Retail | ₹450 | ₹15 | 30 | Market pays double for each rupee of profit |
| Delta Metals | ₹120 | ₹12 | 10 | Low multiple, check if profit is cyclical |
What happens when earnings or price change
Say the price falls 20% to ₹240 while EPS stays at ₹20. The PE ratio drops to 240 ÷ 20 = 12, though the business did not change. Say instead that profit rises 20% to ₹72 crore and the price stays at ₹300. EPS becomes ₹24 and the PE ratio falls to 12.5. The ratio can move because price or earnings changed, so find out which one moved.
One-time gains and dilution
Now suppose ₹15 crore of Beta’s ₹60 crore profit came from a one-time asset sale. Recurring profit is ₹45 crore, so recurring EPS = 45 ÷ 3 = ₹15 and the PE ratio on recurring earnings = 300 ÷ 15 = 20. That is far higher than the headline 15. Or suppose convertibles lift the share count to 3.3 crore. Diluted EPS = 60 ÷ 3.3 = about ₹18.18 and the ratio = 300 ÷ 18.18 = about 16.5.
The ratio also links to book value. If Beta’s equity is ₹400 crore, return on equity is 60 ÷ 400 = 15%, book value per share is 400 ÷ 3 = ₹133.33 and the PB ratio is 300 ÷ 133.33 = 2.25. Check: 2.25 ÷ 0.15 = 15, the same as the PE.
When the PE Ratio Works and When It Misleads
It works best for profitable, stable businesses. It works less well in several cases.
Cyclical companies
Steel, cement, chemicals and commodity firms earn very high profits at the top of a cycle and very low profits at the bottom. At the peak the multiple looks low, which tempts buyers just before profits fall. Look at average earnings over a full cycle instead.
Loss-making and early-stage companies
A company with negative EPS has no usable PE. Use revenue growth, cash burn and the path to profit instead. Financials led the FPI exit in 2026, as our study of sectors hit by FII selling shows, so multiples in that group can shift quickly.
Heavy foreign selling can lower prices and so lower the multiple even when profits are unchanged. Our explainer on how FII flows affect the stock market shows the channels.
Where to Check Earnings and Price Data
Use official filings for the inputs and treat a website’s ready-made ratio as a starting point. Screeners may use standalone or consolidated profit and basic or diluted EPS, so two sites can show different figures. Page layouts change, so check the official site for each item.
| Source | What you can get | Note |
|---|---|---|
| Company results filing on NSE or BSE | Net profit, EPS basic and diluted, share count | Use the latest four quarters for trailing PE |
| Annual report | Notes on exceptional items and dilution | Needed to find recurring earnings |
| NSE Indices factsheets | P/E, P/B and dividend yield for an index | Index level, not single stock |
| Exchange quote page | Current market price | Price is the only input that moves during the day |
To follow the wider market, read the latest FII DII data today and the monthly FII and DII figures and check whether institutional flows might be moving prices.
Pros and Cons of PE Ratio
| Pros | Cons |
|---|---|
| Simple to calculate and widely quoted. | Depends on accounting profit, which can be managed or distorted. |
| Links price directly to earnings, the source of long-term value. | Ignores debt, so two firms with different borrowing look alike. |
| Easy to compare firms in the same sector. | Meaningless for loss-making firms. |
| Works for whole indices and sectors too. | Misleads for cyclical firms at the peak or the bottom. |
| Turns into earnings yield for comparison with bank rates. | Trailing and forward versions can tell opposite stories. |
PE Ratio Checklist and Common Mistakes
- Confirm the business type and whether profit is stable or cyclical.
- Calculate the ratio from the latest filing using profit and share count on the same basis.
- Strip out one-time gains and losses to find recurring EPS.
- Compare with the company’s own history and with listed peers.
- Add growth with the PEG ratio, and look at debt and return on equity.
- Read the annual report notes before relying on any number.
Common mistakes to avoid
Treating a low ratio as proof of a bargain. Profit may be about to fall. Comparing across sectors. A bank and a software firm carry very different multiples. Mixing trailing and forward figures. Ignoring dilution when convertibles or stock options are large. Using a screener value without checking its basis.
Frequently Asked Questions
What is the PE ratio in simple words?
The PE ratio compares a stock’s market price with its earnings per share. A PE ratio of 20 means you pay ₹20 for every ₹1 of yearly profit.
How do you calculate the PE ratio of a stock?
Divide the current market price by earnings per share. You can also divide market capitalisation by net profit attributable to shareholders.
What is a good PE ratio?
There is no single good number. It depends on the sector, growth and risk. Compare a stock with its own history and its peers rather than with a fixed cut-off.
Is a low PE always better?
No. A low ratio can mean the stock is cheap, or that investors expect profits to fall. Check earnings quality, debt and growth before drawing a conclusion.
What is the difference between trailing and forward PE?
Trailing PE uses profit of the last 12 months. Forward PE uses an estimate of next year’s profit, so it depends on the quality of that forecast.
The Bottom Line
The PE ratio is the quickest way to see how much the market pays for each rupee of profit. It suits steady, profitable businesses and fails for loss-makers and cyclical firms. Read it next to growth, debt, return on equity and the company’s own history, and clean out one-time items first.
Our practical next step: pick one company you follow, pull its last four quarters of profit and share count from the exchange filing, and calculate its PE ratio by hand the way the worked example does. Then check the latest FII and DII data to see how institutional flows treat the sector, and browse more explainers in our blog category.
Sources: Nifty 50 factsheet on the NSE Indices website; NSE; BSE; SEBI. Worked examples use hypothetical numbers checked by calculation.
Disclaimer: This article is for educational purposes only and is not investment advice. Please consult a SEBI-registered advisor before making investment decisions.
