Price-to-earnings ratio: what it is and why small business owners should know it

Published Saturday 8 August 2026

Table of contents

• What is the price-to-earnings ratio?
• How to calculate the price-to-earnings ratio
• Types of P/E ratios
• What's a good P/E ratio?
• Why the P/E ratio matters for small business owners
• Limitations of the P/E ratio
• P/E ratio vs other valuation metrics
• Simplify your business finances with Xero
• FAQs on the price-to-earnings ratio

Key takeaways

• The price-to-earnings ratio (P/E ratio) compares a company's share price to its earnings per share, giving you a quick snapshot of how the market values a business relative to its profits.
• Small businesses can adapt the P/E ratio for private valuations, though private companies typically trade at lower multiples (four to 10 times earnings) than public ones due to reduced liquidity.
• There are two main types: the trailing P/E ratio uses the past 12 months of actual earnings, while the forward P/E ratio relies on projected future earnings.
• No single P/E number is universally "good" or "bad," so you should always compare ratios within the same industry and consider additional metrics before making decisions.

What is the price-to-earnings ratio?

The price-to-earnings ratio, often called the P/E ratio, is one of the most widely used metrics in finance. It tells you how much investors are willing to pay for every dollar of a company's earnings, making it a straightforward way to gauge whether a stock or business might be overvalued, undervalued, or fairly priced.

In simple terms, the P/E ratio measures the relationship between a company's market price and its profitability. A higher ratio generally suggests that investors expect strong future growth. A lower ratio may indicate that a company is undervalued or that growth expectations are modest.

How the P/E ratio works

Think of the P/E ratio like the price tag on a rental property compared to the annual rent it generates. If a property costs $200,000 and brings in $20,000 per year in rent, you're paying 10 times the annual income. That's essentially what the P/E ratio does for a business: it tells you how many years of current earnings you'd need to justify the price.

When investors see a P/E ratio of 20, they know the market is pricing that company at 20 times its annual earnings. This ratio helps you compare businesses of different sizes on an even playing field. A $10 billion company and a $100 million company can both have a P/E ratio of 15, meaning investors value each dollar of their earnings equally.

The P/E ratio also reflects market sentiment. Companies in fast-growing industries often carry higher P/E ratios because investors expect earnings to increase significantly over time. More established businesses in slower-growth sectors tend to have lower ratios.

How to calculate the price-to-earnings ratio

Calculating the P/E ratio is straightforward once you have two pieces of information: the current share price and the earnings per share (EPS). The formula is:

P/E ratio = share price / earnings per share (EPS)

Earnings per share represents a company's net profit divided by its total number of outstanding shares. It tells you how much profit the company generates for each share of stock. You can typically find EPS on a company's income statement or through financial data providers.

P/E ratio calculation example

Here's how to work through a P/E ratio calculation with realistic numbers:

1. Find the current share price. Suppose a company's stock is currently trading at $75 per share.
2. Determine the earnings per share. The company reported net income of $50 million over the past 12 months and has 10 million shares outstanding. Divide net income by outstanding shares: $50,000,000 / 10,000,000 = $5.00 EPS.
3. Apply the P/E formula. Divide the share price by EPS: $75.00 / $5.00 = 15.
4. Interpret the result. A P/E ratio of 15 means investors are paying $15 for every $1 of the company's annual earnings. You can now compare this figure to competitors and industry averages to determine whether the stock looks attractively priced.

Types of P/E ratios

Not all P/E ratios are calculated the same way. The two most common versions differ based on whether they look backward at historical earnings or forward at projected earnings.

Trailing P/E ratio

The trailing P/E ratio uses the company's actual earnings from the past 12 months. Because it relies on real, reported financial data, it's considered more reliable and objective. You'll find this version quoted most often on financial websites and in stock screeners.

The downside is that trailing P/E looks in the rearview mirror. If a company's earnings have recently changed dramatically (up or down), the trailing ratio may not reflect the business's current trajectory. Still, for most comparisons, trailing P/E provides a solid baseline.

Forward P/E ratio

The forward P/E ratio uses estimated earnings for the next 12 months, typically drawn from analyst forecasts. This version is useful when you want to understand how the market values a company's future potential rather than its recent past.

The trade-off is accuracy. Projections are educated guesses, and if actual earnings come in higher or lower than expected, the forward P/E ratio can shift significantly. It's best used alongside the trailing P/E ratio for a more complete picture.

What’s a good P/E ratio?

There's no single number that qualifies as a universally "good" P/E ratio. What counts as reasonable depends heavily on the industry, the company's growth stage, and broader market conditions.

As a general reference point, the long-term median P/E ratio for the S&P 500 has historically been around 16 to 18.

A P/E ratio below 15 might suggest a stock is undervalued, while a ratio above 25 could indicate that investors are pricing in significant future growth. However, these are rough guidelines, not hard rules.

P/E ratios by industry

Different industries carry very different average P/E ratios. Technology companies, for example, often have P/E ratios of 25 to 40 or higher because investors expect rapid growth. Utility companies, on the other hand, typically sit in the 12 to 18 range because their revenue streams are more stable and predictable.

Here are some typical industry ranges to keep in mind:

• Technology and software: 25 to 40+
• Healthcare and pharmaceuticals: 15 to 30
• Financial services: 10 to 18
• Consumer staples: 15 to 22
• Energy and utilities: 10 to 18
• Retail: 15 to 25

These ranges shift over time based on economic cycles and interest rates. Always compare a company's P/E ratio to its direct competitors rather than to the market as a whole.

P/E ratios for small businesses

Private businesses typically trade at P/E multiples of four to 10 times earnings, significantly lower than their publicly traded counterparts. The main reason for this discount is liquidity.

Shares in a public company can be sold on an exchange within seconds, while selling a private business is a lengthy, complex process.

Other factors that affect a small business's earnings multiple include the company's size, growth rate, customer concentration, and how dependent the business is on its owner.

A business with diversified revenue, strong systems, and a management team that operates independently of the owner will generally command a higher multiple.

Why the P/E ratio matters for small business owners

Even if you don't invest in public markets, understanding the P/E ratio gives you a practical framework for thinking about business value. It connects profitability to price in a way that's easy to grasp and apply.

Using the P/E ratio when valuing your business

When it comes time to sell, seek investment, or simply understand what your business is worth, the P/E ratio offers a useful starting point. Buyers and investors often look at comparable publicly traded companies, then apply a discount to arrive at a private business valuation.

For example, if similar public companies in your industry trade at a P/E of 20, a private business might be valued at eight to 12 times earnings after accounting for the liquidity discount and size differences.

Knowing these benchmarks helps you set realistic expectations and strengthens your position in negotiations.

Your accountant or financial advisor can help you identify the right comparables and adjustments for your specific situation.

Using the P/E ratio to evaluate investments

If you're considering investing your business profits, the P/E ratio is one of the first metrics to check. It helps you quickly compare opportunities and spot potential red flags.

A company with a P/E ratio significantly higher than its industry average may be overvalued, unless there's a compelling growth story to justify the premium.

Conversely, a very low P/E ratio could signal a bargain or could indicate deeper problems like declining revenue or management issues.

Here are some practical checks when evaluating investments:

• Compare the company's P/E ratio to its industry average.
• Look at both trailing and forward P/E to understand the trend.
• Consider the company's earnings growth rate alongside the ratio.
• Check whether recent one-time events have distorted earnings.

Limitations of the P/E ratio

The P/E ratio is a helpful starting point, but it has real limitations you should keep in mind:

• Negative earnings break the formula. If a company is losing money, the P/E ratio becomes meaningless or negative, which makes comparison difficult. Many startups and high-growth companies fall into this category.
• One-time events can distort results. A large asset sale, a legal settlement, or a restructuring charge can temporarily inflate or deflate earnings, making the P/E ratio misleading. Always check whether reported earnings include unusual items before drawing conclusions.
• Debt levels aren't captured. Two companies can have identical P/E ratios but very different levels of debt. A highly leveraged company carries more risk that the P/E ratio alone won't reveal.
• Different accounting methods affect comparability. Companies using different depreciation methods or measuring profitability may report different earnings for similar underlying performance. For these reasons, the P/E ratio works best as one tool among several rather than a standalone measure.

P/E ratio vs other valuation metrics

The P/E ratio is one of many valuation tools available to you. Understanding how it compares to alternatives helps you choose the right metric for your situation.

P/E ratio vs PEG ratio

The PEG ratio (price/earnings-to-growth) builds on the P/E ratio by factoring in earnings growth. You calculate it by dividing the P/E ratio by the annual earnings growth rate.

A PEG ratio of one is generally considered fair value, meaning the P/E ratio is in line with the company's growth rate. A PEG below one may suggest the stock is undervalued relative to its growth. The PEG ratio is particularly useful for comparing companies with different growth rates within the same industry.

P/E ratio vs EV/EBITDA

The EV/EBITDA ratio (enterprise value to earnings before interest, taxes, depreciation, and amortization) takes a broader view than the P/E ratio. It accounts for a company's total value, including debt, and strips out the effects of financing decisions, tax structures, and non-cash charges.

This makes EV/EBITDA especially useful when comparing companies with different capital structures or across borders.

For small business owners evaluating an acquisition or merger, EV/EBITDA often provides a more accurate picture than the P/E ratio alone. You can learn more about related profitability ratios to round out your analysis.

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Understanding valuation metrics like the P/E ratio starts with having clean, accurate financial data. When your books are organized and up to date, you're in a stronger position to assess your business's value and make confident financial decisions.

Xero's online accounting software helps you track income, expenses, and profitability in real time. Whether you're preparing for a valuation, evaluating an investment, or simply keeping your finances in order, Xero gives you the clarity and control to move forward with confidence.

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FAQs on the price-to-earnings ratio

Here are answers to some common questions about the price-to-earnings ratio and how it applies to your business.

What does a P/E ratio of 15 mean?

A P/E ratio of 15 means investors are paying $15 for every $1 of a company's annual earnings. It suggests moderate market expectations, roughly in line with the long-term S&P 500 median.

Is a high P/E ratio good or bad?

A high P/E ratio isn't automatically good or bad; it often signals that investors expect strong future earnings growth, but it can also mean the stock is overpriced. Always compare the ratio to industry peers and the company's historical range.

Can you use the P/E ratio for a private business?

Yes, but with adjustments. Since private businesses don't have a market share price, you'd use the business's total value (or asking price) divided by annual net earnings. Private companies typically have lower P/E multiples than public ones due to reduced liquidity and higher risk.

What P/E ratio is too high?

There's no absolute cutoff, but a P/E above 30 to 40 is generally considered high for most industries. The key is whether the company's growth prospects justify the premium, so compare the ratio to industry averages before deciding.