Price-to-Earnings Ratio (P/E)🇦🇷
The P/E (Price-to-Earnings) is the most widely used stock valuation metric. It shows how many times a company's earnings per share you're paying for the stock. A P/E of 20 means you pay $20 for every $1 of annual earnings. This calculator also includes PEG ratio to account for earnings growth.
When to use this calculator
- Evaluate a stock before buying.
- Compare P/E ratios across companies in the same sector.
- Calculate PEG ratio adjusted for growth.
- Estimate fair value based on sector P/E average.
- Screen for undervalued stocks.
Real Example: Growth Tech Stock
- Data: Price = $150, EPS = $8, Sector Avg P/E = 15, Expected Growth = 10% annual.
- Formula: P/E = $150 ÷ $8 = 18.75.
- PEG: 18.75 ÷ 10 = 1.88 — slightly expensive for its growth rate.
- Fair Value: EPS × Sector P/E = $8 × 15 = $120.
- Interpretation: Trading 25% above fair value. Overvalued unless growth accelerates.
How it works
1 min readWhat is the P/E Ratio
The P/E (Price-to-Earnings) or PER is the most common valuation metric in stock investing. It tells you how many times a company's annual earnings per share you're paying for the stock. Calculated as P/E = Stock Price ÷ Earnings Per Share (EPS).
Typical P/E Ranges by Sector (Historical)
| Sector | Avg P/E |
|---|---|
| Growth Tech | 25 – 40 |
| Mature Tech (Apple, MSFT) | 25 – 35 |
| Consumer Staples | 18 – 25 |
| Financials | 8 – 15 |
| Energy | 10 – 18 |
| Utilities | 15 – 22 |
| Industrials | 15 – 25 |
| S&P 500 Historical Average | ~16 |
High P/E ≠ Expensive, Low P/E ≠ Cheap
A P/E of 40 can be justified for a company growing at 30% annually (PEG = 1.33). A P/E of 8 can be a value trap if the industry is declining. PEG (P/E ÷ Growth Rate) helps: PEG < 1 is often attractive.
When to Use & Common Mistakes
Frequently asked questions
What is a good P/E ratio?
It depends on the sector. Growth tech: 25–40. Mature tech: 25–35. Consumer staples: 18–25. Finance: 8–15. Utilities: 15–22. Always compare to sector average and historical norms.
Is a low P/E ratio always good?
No. A low P/E can signal problems—weak earnings growth, industry decline, cyclical downturn, or deteriorating margins. Always investigate why the P/E is low.
What is the PEG ratio?
PEG = P/E ÷ Expected Growth Rate. A PEG below 1.0 suggests the stock is cheap relative to its growth potential. PEG > 2.0 generally signals overvaluation.
What is forward P/E?
Forward P/E uses next year's projected earnings instead of trailing earnings. It's more relevant for growth companies, but projections carry uncertainty.
Can you use P/E for unprofitable companies?
No. P/E doesn't work for companies with negative earnings. Use Price-to-Sales (P/S) or other metrics for pre-revenue or unprofitable companies.
What's the current P/E of the S&P 500?
Historically around 16–17. As of 2024–2026, it's around 20–25, above the long-term average, driven by large-cap tech concentration.
How do you calculate fair value using P/E?
Fair Value = EPS × Sector Average P/E. Compare this to the actual stock price to determine if it's overvalued or undervalued.
Why does P/E vary so much by sector?
Growth expectations differ. Tech grows faster and commands higher P/Es. Utilities are stable and have lower P/Es. Growth vs. mature industries have vastly different valuations.
What's the difference between trailing and forward P/E?
Trailing P/E uses actual earnings from the last 12 months (more reliable). Forward P/E uses projected next-year earnings (useful for growth analysis but uncertain).