The PE ratio measures how much investors are willing to pay for each dollar of a company's earnings. It's one of the most widely used valuation metrics.
If a stock trades at $100 and EPS is $5, the PE ratio is 20. This means investors pay $20 for every $1 of earnings.
A lower PE may suggest undervaluation, while a higher PE could indicate growth expectations. Compare PE within the same industry — tech stocks typically have higher PEs than utilities.
The PE ratio is the most widely used valuation metric because it's simple, widely available, and intuitive. It tells you how much the market is willing to pay for each dollar of a company's earnings. A PE of 20 means investors are paying $20 for every $1 of annual earnings — they expect the company to grow significantly.
During earnings season, the PE ratio is one of the most-watched numbers. When a company reports earnings that beat or miss expectations, the PE ratio immediately adjusts, often causing the stock price to move 3-10%. Professional investors use PE ratios alongside other metrics to identify undervalued or overvalued stocks.
A good PE ratio trades near or below its industry's average. Here are typical ranges by sector:
| Industry | Average PE | Reason |
|---|---|---|
| Technology (Software) | 39-43 | High growth expectations, innovation |
| Technology (Semiconductors) | 43-44 | Cyclical with high growth potential |
| Healthcare (Products/Devices) | 30-56 | Varies by subsector and growth |
| Utilities (Electric) | 14-22 | Stable, regulated cash flows |
| Healthcare (Facilities) | 13-21 | Lower growth, stable demand |
Data sources: FullRatio, NYU Stern, CSI Market (2025-2026). Values fluctuate with market conditions.
Consider two companies in the technology sector: Company A has a PE of 15, Company B has a PE of 40. Company A might be undervalued, or it might have lower growth prospects. Company B might be overvalued, or it might be growing three times faster. The PE ratio alone doesn't tell you which is the better investment — you need to consider growth rates, industry context, and competitive advantages.
During the 2008 financial crisis, many financial stocks traded at PE ratios below 5. Some were genuine bargains that delivered massive returns. Others were value traps — they appeared cheap because earnings were artificially inflated or about to collapse. This illustrates why PE ratio must be combined with earnings quality analysis and growth projections.
Use the PEG ratio for growth companies: PEG = PE ratio ÷ earnings growth rate. A PEG below 1.0 may indicate undervaluation, while above 2.0 may suggest overvaluation. A PE of 40 with 50% growth (PEG = 0.8) can be attractive.
Compare PE to the company's own history: Look at the 5-year average PE. If the current PE is 15% below the historical average while fundamentals remain strong, the stock may be undervalued.
Check earnings sustainability: Verify that earnings are backed by operating cash flow. If earnings are growing but cash flow is flat or declining, accounting practices may be inflating reported profits.
Use Shiller PE (CAPE ratio) for market timing: The cyclically-adjusted PE ratio averages earnings over 10 years to smooth out business cycles. When CAPE is above 30, the market has historically underperformed over the next 10 years.
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Try PE Ratio Calculator →What is a PE ratio?
PE (Price-to-Earnings) ratio = Stock Price ÷ Earnings Per Share. It shows how much investors pay for $1 of earnings. A PE of 20 means you're paying $20 for every $1 the company earns. Lower PE suggests cheaper valuation, but may reflect slower growth expectations. Always compare PE within the same industry.
What is a good PE ratio?
The S&P 500 historical average is about 15-16. Below 15 may indicate value (or trouble); above 25 suggests high expectations. Tech companies often trade at 25-40+ PE due to growth expectations. Utilities trade at 15-20 PE. The key is comparing to industry peers and the company's own historical range, not an absolute number.
Trailing vs. forward PE?
Trailing PE uses the last 12 months of actual earnings. Forward PE uses analyst estimates for the next 12 months. Forward PE is usually lower (companies are expected to grow), but relies on estimates that may be wrong. Check both — if forward PE is much lower than trailing, the market expects significant earnings growth.