The price-to-earnings (P/E) ratio divides a stock's price by its earnings per share (EPS). It tells you how much investors are paying for each dollar of earnings. A P/E of 20 means investors pay $20 for every $1 of annual earnings. Lower P/E can mean cheaper valuation or slower expected growth; higher P/E can mean expensive or high growth expectations.

Can a stock have a negative P/E ratio?

Yes — when a company has negative EPS (a net loss), the P/E ratio is technically negative or meaningless. Most financial sites show 'N/A' for P/E when earnings are negative. For money-losing companies, investors use other metrics like price-to-sales (P/S), EV/EBITDA, or price-to-free-cash-flow instead.

Is a low P/E always better?

Not necessarily. A low P/E can indicate a value opportunity, but it can also reflect a 'value trap' — a company with declining earnings, structural headwinds, or poor management. The P/E should always be evaluated alongside earnings growth rate, competitive position, balance sheet quality, and sector context. A slow-growth utility at 14x is not inherently more attractive than a fast-growing tech company at 28x.

What is the PEG ratio and how does it relate to P/E?

The PEG ratio divides the P/E by the annual earnings growth rate. A PEG of 1.0 is considered fair value by many analysts — it means you're paying one dollar of P/E for each percentage point of growth. A PEG below 1.0 suggests undervaluation; above 2.0 may suggest overvaluation. A stock with a 30x P/E and 30% annual growth has a PEG of 1.0 — potentially as fairly valued as a stock with a 15x P/E and 15% growth.

P/E Ratio Calculator

Built and verified by Akshaya Panda · Last updated September 4, 2026

Calculate a stock's price-to-earnings ratio, compare it to S&P 500 history and sector averages, and see the implied fair value at different multiple targets.

Stock Price ($)

Earnings Per Share (EPS $) Use TTM EPS for trailing P/E, or forward EPS estimate

Sector

Expected Annual EPS Growth (%) Used to calculate PEG ratio

Price-to-Earnings Ratio

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vs S&P 500 LT Avg (17x)

17x

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vs Sector Avg

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PEG Ratio

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Implied Fair Value at P/E Targets

P/E 12x

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P/E 17x

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P/E 20x

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P/E 25x

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Sector avg

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What Is the P/E Ratio?

The price-to-earnings ratio (P/E) is the most widely used stock valuation metric. It answers a simple question: how much are investors paying for each dollar of company earnings? A P/E of 20 means the market pays $20 for every $1 of annual earnings. A P/E of 10 means $10 per dollar of earnings.

Two versions are commonly used: trailing P/E uses the last 12 months of actual reported EPS; forward P/E uses analyst consensus estimates for the next 12 months. Forward P/E is typically lower for growing companies (because future earnings are projected to be higher) and is most useful when comparing fast-growing businesses. Trailing P/E is more reliable for stable, mature companies because it uses real numbers.

Historical S&P 500 P/E Averages

Period	S&P 500 Avg P/E	Context
1900–2000 (century avg)	~14–16x	Long-run baseline; higher interest rates historically
2000 dot-com peak	~44x	Speculative peak; crashed 50% over 2 years
2009 financial crisis low	~10–12x	Earnings collapsed; P/E temporarily spiked before recovering
2010–2019 avg	~20–22x	Low-rate environment supported higher multiples
2024–2025	~22–26x	AI/tech premium; above long-run average

P/E by Sector (2025 Approximate Averages)

Sector	Typical P/E Range	Why Higher or Lower
Technology	25–35x	High growth expectations, scalable business models
Consumer Discretionary	22–28x	Growth brands command premiums; cyclical risk
Healthcare	20–25x	Defensive growth; patent pipeline uncertainty
Industrials	20–26x	Cyclical; infrastructure spending drives premium
Consumer Staples	22–26x	Defensive / recession-resistant; slow growth
Utilities	18–22x	Stable, regulated earnings; interest-rate sensitive
Materials	16–20x	Commodity-linked earnings; cyclical
Financials	12–16x	Low multiples due to cyclicality and regulatory risk
Energy	10–14x	Commodity-driven earnings volatility; capital intensive

P/E alone doesn't make a buy or sell decision. A stock at 35x P/E might be cheap if it's growing earnings at 40% per year. A stock at 10x P/E might be a value trap if earnings are declining. Always combine P/E with the earnings growth rate (PEG ratio), the balance sheet (P/B ratio), and competitive position before drawing conclusions. See the stock analysis guide for the full framework.

The P/E ratio works best when comparing companies within the same sector and with similar growth profiles. Cross-sector comparisons are less meaningful — a 13x bank and a 28x software company can both be fairly valued. For growth investors, also check the EPS growth calculator to model what future earnings imply for price at current multiples. For balance-sheet-focused analysis, the price-to-book calculator adds the P/B ratio perspective.

Frequently Asked Questions

What is a good P/E ratio for a stock?

The S&P 500 long-run average P/E is approximately 15–17x. Since 2010, the market has traded at 20–25x due to low interest rates and tech-sector growth. A "good" P/E depends on the sector (tech trades at 25–35x; financials at 12–15x), growth rate, and interest rate environment. Compare within sector and weigh the PEG ratio (P/E ÷ growth rate) for a growth-adjusted view.

What is the difference between trailing and forward P/E?

Trailing P/E uses the last 12 months of actual EPS. Forward P/E uses analyst estimates for the next 12 months. For stable companies, trailing P/E is more reliable (real data). For fast-growers, forward P/E is more relevant because current earnings dramatically understate the near-future earnings power.

What is the PEG ratio?

PEG = P/E ÷ annual EPS growth rate. A PEG of 1.0 means you're paying one dollar of multiple for each percentage point of growth — considered fair value by many analysts. PEG below 1.0 suggests growth is cheap; above 2.0 may indicate overvaluation relative to growth. A 30x P/E stock growing at 30% (PEG 1.0) may be more attractive than a 15x P/E stock growing at 5% (PEG 3.0).

Why does the P/E ratio matter for investors?

P/E is a quick signal of market expectations. High P/E means the market expects strong future earnings growth — so any earnings miss or growth slowdown is punished severely. Low P/E means expectations are muted — upside surprises can trigger large price gains. Understanding what's priced in helps you evaluate risk/reward.

What P/E ratio is too high to buy a stock?

There is no universal "too high" threshold. In the dot-com era, stocks at 100x+ P/E crashed 80–90%. But quality compounders at 35–40x P/E have rewarded patient investors when earnings grew to justify the multiple. The right question is: does the earnings growth rate justify the multiple? Use the PEG ratio and the earnings growth calculator to stress-test the required growth to earn a market return at the current price.

How we build our calculators

Sources & method

This calculator implements the price-to-earnings ratio — standard financial mathematics that no single body maintains as an official standard. The formula is shown on this page so you can verify it.

Not financial or tax advice. This is an educational estimator. It does not know your full situation, and tax rules change. Akshaya Panda, who builds and verifies these tools, is an engineer — not a financial adviser, accountant, or tax professional. Before acting on a result that matters, check it with someone licensed to advise you.