What is the PE Ratio? How to Use the Formula Properly.

Most Investors Don't Understand the PE Ratio! A Complete PE Ratio Guide Helps You Compare Stocks Properly + Formulas, Calculations & Examples

The Price-Earnings Ratio is a commonly used and often misunderstood calculation for determining a company’s value. The PE Ratio is only useful for comparing similar companies in the same industry with similar business models. It should not be used to compare radically different businesses.

What is the PE Ratio?

The Price-Earnings Ratio (PE Ratio or PER) is a formula for performing a company valuation. It is calculated by dividing the current stock price by the previous 12 months’ earnings per share (EPS). A PE Ratio of 12 means you would pay $12 for every $1 of earnings if you invested. It should only be used to compare companies in the same industry.

How to Calculate The PE Ratio

The PE Ratio has two parts.

Part 1. Calculate the Earnings per Share. EPS = (Earnings or Net Income for the previous 12 months) divided by (Number of Shares Outstanding)

Part 2. We can now calculate the PE Ratio.  PE Ratio = (Current Share Price) divided by (Earnings per Share EPS)

The PE Ratio Formula

PE Ratio = Current Stock Price / Previous 12 Months Earnings Per Share.

PE Ratio Formula & Calculation
PE Ratio Formula & Calculation

What Does the PE Ratio Mean?

The PE ratio enables you to understand how much it will cost you to buy a portion of a companies profit.  If a company has a PE Ratio of 25, it will cost you $25 for each $1 of company profit.

Imagine you want to buy an Icecream Stand.  The Owner wants to sell that stand to you for $10,000.  The Icecream Stand makes a yearly profit after tax of $2,000.  This means if I want to buy this profit of $2,000, it will cost me $10,000.  So the PE Ratio is $10,000 / $2,000 = 5.  In other words, it would take me five years to make my money back on this investment.

This is what the PE Ratio or the “Multiple” tells us.  In the example above, I used the case of buying a whole business, and we are considering all of the profits.  The PE Ratio achieves this same goal by using the Individual Share Price / Earnings per Share as we are not buying the whole company, just a portion of it.

The PE Ratio can tell you what kind of premium investors are willing to pay to get a piece of this company.   PE Ratios should always be considered in the context of the industry group.

Video: Price Earnings Ratio Explained

Video From The Liberated Stock Trader Pro Training Course 2022

Industry PE Ratio

PE Ratios are best deployed to compare companies within the same industry.  Some industries may have a very high average PE Ratio and some a very low PE Ratio, depending on where the industry is in its lifecycle.  If an industry is new, fast-growing, and requires a lot of investment, the PE ratio may well be high on average, such as the Big Data Analytics industry.  If an industry is stable and slow-growing, the average PE ratio may be lower, for example, in the Utilities Industry.

This makes comparing companies in different industries with the PE ratio not advisable.

What is a Good PE Ratio?

A good PE ratio is a lower PE Raio. When comparing two companies in the same industry with the same future growth and earnings expectations, then the better PE ratio is the lower one. The company with the lower PE ratio represents better value as you are paying less per share for the same earnings and growth potential.

There is no such thing as a good PE ratio for all companies; however, we can say that a PE Ratio in general under 25 is ok and suggests the company is reasonably priced.  A PE Ratio over 200 would indicate that the company share price is way more than its ability to generate matching profits.

Is a Company Cheap, Fairly Priced, or Overpriced?

P/E Ratio - How Strong is the Stock compared to the Competition
PE Ratio – How Strong is the Stock compared to the Competition.

The Price to Earnings ratio is a simple calculation that may take a little bit of time to understand.  But once you understand it, it can be beneficial.

If you compare the PE Ratio of companies in the same industry, this will tell you which companies are perceived to have the brightest future or the best products or services; as the investors are willing to pay more for a share of one company as opposed to another company that is in the same line of business.

Is a High PE Ratio Good?

A high PE ratio can be both good and bad, meaning it can indicate a company with a great future or indicate an excessively overpriced company.  It depends on what you believe the company’s future outlook to be.

For example, Company A has a  PE Ratio of 100.  If 100 is the highest PE in the industry, then investors believe this company has the best profit growth potential in the future.  This means that the market participants are willing to buy the stock because it has excellent growth prospects.

What is a High PE Ratio?

Most investors should consider a high PE Ratio to be over 40. A high PE Ratio is wholly dependent upon the ability of the company to maintain fast growth, increased sales, and earnings. A high PE Ratio means the investors are expecting higher future returns and continued growth.

Currently, the PE Ratio for the S&P 500 is high at 35.

Amazon or Netflix PE Ratios are usually over 100.  This is because investors are willing to pay higher prices for the shares because of perceived future growth.  For example, Amazon has razor-thin margins and invest so much of its revenue into penetrating new markets and building technology and logistics centers that there is very little profit left over.  This means the High Share Price dividend by the Low Earnings equals a high PE Ratio.  As investors are still willing to pay a lot for Amazon shares, the PE remains high.  If the investors lose confidence in the company’s ability to continue growing faster, they would experience fear, sell the stock, and the stock price would crash.  This means with a lower stock price; the PE Ratio would also drop to something more reasonable.

High PE Ratios usually mean high growth potential, but if investors lose confidence the stock price can plummet.

What is an Average PE Ratio?

Company B has a  PE of 25; if 25 were the industry average, then this company would be seen as a fair value for the industry.  This essentially means the investors think this company is neither a high-performance, high-growth stock nor an underperformer with fewer profits compared to the competition.

Is a Low P/ Ratio Good?

Again a low PE Ratio can be good or bad based on the context.  A low PE can be good if the company has grown profits in a growing market. It could indicate that the broader market participants have not realized that this company has a very low valuation compared to its peers.  This is what income investors or value investors like Warren Buffett look for when buying shares in a company.  A company with a low PE and excellent growth and profitability.   As the profits grow, other investors will see that this company is a bargain, and the stock price due to the buyer’s demand will start to increase.

When is a Low PE Ratio Bad?

A low PE ratio can be bad when the company in question is in a declining market, and the prospects are bleak.  As profits decrease, so does the stock price as the current investors are selling the stock, and the demand for the stock is decreasing also.  This is why the earnings season is so important.

A Low PE Ratio Example

Company C has a low PE of 5 compared to the industry average of 25.  This company would be seen as an underperformer / or a stock with potential value.  If the earnings suddenly jumped for this stock, this could potentially be a good bargain.  However, negative earnings would adversely impact the PE Ratio, meaning if the profits were reduced, the PE ratio would increase, which means the stock price would need to fall to compensate for it.

The PE Ratio needs to be combined with other fundamental measures to get a much better picture of the stock.

Is there a Negative PE Ratio?

Yes.  A company can have a negative PE Ratio if it has not made any profit in the previous year.  But it is not possible to put a value or number on the ratio because the PE ratio consists of Price divided by Earnings, and if there are no earnings, the formula does not work. You will often see a negative PE ratio reported as N/A or Blank.

What is the PE Ratio TTM?

The PE Ratio TTM refers to the PE Ratio for the Trailing Twelve Months; this means the price divided by earnings is calculated based on the previous 12 months. The TTM is different from the calendar year, which is from January 1st to December 31st.

What is the Forward PE Ratio?

The forward PE Ratio is calculated based on the current stock price divided by the company’s estimated earnings for the next full financial year.  This is only an estimate and is calculated based on the average earnings expectations of either a group of analysts or the company’s earnings forecast for the next fiscal year.

Example: Using a PE Ratio to Compare Facebook, Apple, Amazon, Netflix & Google
FAANG Stocks - Quotes - Sentiment - Analysis

Are FAANG Stocks Overpriced or Fair Value

  • Facebook PE Ratio 28
  • Amazon PE Ratio 143
  • Apple PE Ratio 14.8
  • Netflix PE Ratio 135
  • Google (Alphabet) PE Ratio 26.5

The PE Ratio essentially measures how many years it would take the company to buy all its stock back with its earnings.  The value of all the shares divided by the profits of the company.  Depending on the particular industry, a PE ratio may vary, but a typical valuation sought after by a value investor would be something below 20.  So compared to that, the FANG’s could be considered overpriced.

But we need to be clear that these are not normal companies; they are still considered fast-growing technology stocks, with relatively low costs, high earnings, and even higher earnings potential.

While Facebook & Google have a reasonable PE Ratio, and Apple could almost be considered a bargain, both Amazon and Netflix seem to be extremely overpriced.  One of the reasons for this is they are plowing all revenue back into the business to fuel the fast growth.  This reduces the earnings (after expenses) and makes them look on the surface overpriced.

How to use the S&P500 PE Ratio (Shiller Formula)

You can also use the PE ratio to assess if the market is good value, fairly priced, or overpriced.  The chart below shows the Robert Schiller calculation for the PE ratio of the S&P Composite for the last 100 years.  You can see that a PE around 20 is fair value, while very excessive PE valuations have typically been following by crashes or readjustments.

What is the P/E Ratio of the S&P 500? Shiller Formula
What is the PE Ratio of the S&P Composite Index? Shiller Formula

Shiller PE ratio for the S&P 500. The Price-earnings ratio is based on average inflation-adjusted earnings from the previous ten years, known as the Cyclically Adjusted PE Ratio (CAPE Ratio), Shiller PE Ratio, or PE 10 FAQ. Data courtesy of Robert Shiller from his book, Irrational Exuberance.

The market is approaching a very high valuation historically, up there with the 1929 great depression and the Dotcom bust. Interestingly the Financial Crisis was not due to the overvaluation of the stock market but the integrity of the financial system itself. It is a good thing this was a great earnings season because there could be a severe pullback or readjustment if it were not.

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PE Ratio Summary

Having some knowledge that a company will not be declaring bankruptcy anytime soon is the minimum goal; however, the more refined investor will be looking for stocks that are reasonably priced, have low amounts of debt, or at least the ability to repay that debt easily, strong sales growth or revenue growth, a decent amount of cash in the bank, and stable earnings.

Also, if you are familiar with the company’s product and how important it is to the business, it can give you additional insight.

Learn More About the Price Earnings Ratio & All the Fundamental & Technical Analysis Theory


This is an excerpt from the Liberated Stock Trader Book and accompanying Training Course. Chapter 4 – Section 4 – The PE Ratio

Other Chapters of the Liberated Stock Trader Book are listed below

Chapter 1 – Essential Stock Market Knowledge – Fundamentals

This chapter sets the stage for the two key areas of stock market technical analysis and the fundamental analysis of companies including macro and microeconomics

Chapter 2 – What Really Moves Markets - Why do Booms and Busts Occur?

This chapter looks at what REALLY makes the markets move, what causes boom and bust cycles, and how to spot them.

Chapter 3 – How do markets move ? - Stock Market Cycles – Business & Economic Cycles – Kondratieff to Kuznets

What are stock market cycles and the cycles of business and economies?  Important information that you need to appreciate as part of your core analysis.

Chapter 4 – Is the Company in great shape – P/E Ratio

Next we move into fundamental analysis and the financial fitness of a company.  All the major indicators and measures are covered.

Chapter 5 – How to find the best stocks

Stock screening means using criteria to shortlist the kind of stock that you want to purchase.  A vital part of any stock market training

Chapter 6 – Chart Reading made easy - Japanese Candlesticks – Bullish Reversal Patterns

Once you know the business climate, the state of the economy and you have shortlisted the stocks you want to buy.  The next thing to do is the technical analysis.  Even if the company looks great on paper, if the stock price is plummeting you do not want to buy it until it has bottomed out.  This is called catching a falling knife.  This is what chart patterns and technical analysis help with.

Chapter 7 – Trend Lines and Price Patterns - How to draw trend lines

Here we get into the art of drawing on charts to help you visualize the Supply and Demand on the stock, the direction of the trend, and estimate how long the trend will last.  Vital for you to establish buy and sell signals.

Chapter 8 – Chart Indicators are your friends! – ROC Rate of Change Indicator

Which indicators should you use, there are literally hundreds of stock chart indicators?  Each has a specific use case and application, which should you use?

Chapter 9 – Chart Indicators Volume - The Price Volume Relationship

Volume is a vital indicator along with the price.  Both of these you need to understand in granular detail, you will learn everything you need to know.

Chapter 10 - Advanced Stock Charting Techniques Parabolic SAR

Moving to advanced technical analysis we cover indicators such as parabolic SAR and point & figure charts.

Chapter 11 - Sentiment Indicators & Trading the News - How to trade the news

How are the market participants feeling?  Positive, Negative, or indifferent.  Consider that 90% of people fail to beat the average market returns, sentiment indicators can be a great contrary indicator.  Learn how to use them to your advantage.

Chapter 12 - Trading Strategy - What type Of Investor are you?

Understanding how you want to invest, how much time you have, and your time horizon.  These questions all help you to understand what type of investor you want to be, this then enables you to select the right strategy for you.  Then we move on to building your stock investing system, a critical element to your plan.


  1. Hi Punit

    Higher PE does not mean a better option it just means the investors have placed a higher valuation on the company and have a higher expectation on future earning and growth.

    Warren Buffets major holdings, COP, PSX, PKX, WFC etc all have a PE below 10.

  2. hiii i actually have one doubt that why does higher pe ratio means better option becoz for higher pe ratio company u have to pay more money for earning compare to lower pe ratio.
    eg. 1.i will earn 1 dollar behind every 10 dollar for company with pe 10
    2.i will earn 1 dollar behind every 25 dollar for company with pe 25
    whats better?
    plz explain

  3. It is truly a great and helpful piece of information. I am happy that you simply shared this helpful information with us. Please keep us up to date like this. Thank you for sharing.


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