Quick answer
P/E Ratio = Stock Price / Earnings Per Share (EPS). Example: $150 stock price ÷ $7.50 EPS = P/E of 20x (earnings yield: 5%). The historical S&P 500 average P/E is 15–17x; high-growth tech typically trades at 30–60x+.
How to use this calculator
Enter the Stock Price (current market price per share) and EPS (trailing twelve months earnings per share — found on any financial data site or calculated from the income statement). The calculator shows the trailing P/E ratio and earnings yield. Optionally enter Forward EPS (analyst consensus estimate for the next 12 months) for the forward P/E, and a Target P/E Multiple to see what the stock would be worth at that multiple.
P/E ratio formula
The Price-to-Earnings ratio divides the current share price by earnings per share:
$$\text{P/E Ratio} = \frac{\text{Stock Price}}{\text{Earnings Per Share (EPS)}}$$
EPS is derived from the income statement:
$$\text{EPS} = \frac{\text{Net Income} - \text{Preferred Dividends}}{\text{Weighted Avg. Shares Outstanding}}$$
The earnings yield is the inverse of P/E — it expresses earnings as a return on the share price:
$$\text{Earnings Yield} = \frac{\text{EPS}}{\text{Stock Price}} \times 100$$
Implied fair value at a target P/E multiple:
$$\text{Implied Price} = \text{EPS} \times \text{Target P/E}$$
Trailing P/E vs. forward P/E
| Trailing P/E (LTM) | Forward P/E (NTM) | |
|---|---|---|
| EPS used | Last 12 months actual reported EPS | Next 12 months analyst consensus estimate |
| Reliability | Factual — based on reported results | Estimate — subject to revision |
| For growing companies | Higher (past earnings lower) | Lower (future earnings expected higher) |
| Best used for | Historical comparison, value screening | Growth-oriented valuation, relative comparison |
| Limitation | Backward-looking; may not reflect current trajectory | Analyst estimates can be wrong; EPS revisions move forward P/E |
For a growing company, forward P/E will be lower than trailing P/E. If forward P/E exceeds trailing P/E, analysts expect earnings to decline — a warning signal worth investigating.
Worked examples
| Stock | Price | Trailing EPS | Trailing P/E | Forward EPS | Forward P/E | Earnings Yield |
|---|---|---|---|---|---|---|
| Mature dividend stock | $80 | $6.40 | 12.5x | $6.80 | 11.8x | 8.0% |
| S&P 500 average | — | — | ~17x | — | ~15x | ~5.9% |
| Growth tech stock | $250 | $5.00 | 50x | $8.00 | 31.3x | 2.0% |
| Value stock | $45 | $4.50 | 10x | $5.00 | 9.0x | 10.0% |
P/E benchmarks by sector
| Sector | Typical P/E range | Why high/low |
|---|---|---|
| Technology / Software | 25x – 60x+ | High growth, scalable margins, recurring revenue |
| Healthcare / Biotech | 18x – 35x | Growth + pricing power; biotech can be infinite (no earnings) |
| Consumer Discretionary | 15x – 30x | Cyclical with brand premiums |
| Consumer Staples | 18x – 25x | Stable earnings attract premium; defensive characteristics |
| Industrials | 12x – 20x | Steady but cyclical; capital-intensive |
| Financials (Banks) | 8x – 14x | Leverage-driven; regulatory constraints |
| Energy / Utilities | 8x – 15x | Capital-intensive, commodity exposure, regulated |
Limitations of the P/E ratio
- Meaningless for loss-making companies: A company with negative EPS has no P/E ratio. Use EV/Revenue or Price-to-Sales for pre-profit businesses.
- EPS can be manipulated: Share buybacks reduce shares outstanding and inflate EPS without improving underlying profitability. One-time gains or losses distort reported EPS. Use adjusted or normalised EPS where possible.
- Doesn't account for debt: Two companies with identical P/E ratios but different leverage profiles carry very different risk. A highly leveraged company's P/E will appear low because debt amplifies equity returns — until it doesn't. EV/EBITDA is a better apples-to-apples comparison.
- Not comparable across industries: Comparing a utility's P/E of 12x to a tech company's 40x is meaningless. Compare only against direct sector peers with similar growth rates.
- Ignores growth rate: The PEG ratio (P/E divided by EPS growth rate) adjusts for growth and enables fairer comparison between companies growing at different rates. A P/E of 30x for a company growing at 30%/year (PEG = 1.0) may be cheaper than a P/E of 15x for a company growing at 5%/year (PEG = 3.0).
Frequently asked questions
What is the P/E ratio?
The Price-to-Earnings ratio measures how much investors pay per dollar of annual earnings. P/E = Stock Price / EPS. A P/E of 20 means the stock costs 20 times its annual earnings per share. It is the most commonly cited equity valuation multiple.
What is a good P/E ratio?
Depends on the sector and growth rate. The long-run S&P 500 average is ~15–17x. High-growth tech: 30–60x+. Mature value stocks: 8–15x. A "good" P/E is one that is reasonable relative to peers and justified by the company's growth rate, quality of earnings, and competitive position.
What is the difference between trailing and forward P/E?
Trailing P/E uses actual reported EPS from the last 12 months. Forward P/E uses estimated EPS for the next 12 months. Forward P/E is lower for growing companies (future earnings are higher). If forward P/E > trailing P/E, earnings are expected to decline.
What is earnings yield?
Earnings yield = EPS / Stock Price × 100 = 1 / P/E × 100. A P/E of 20x = 5% earnings yield. Analysts compare earnings yield to 10-year Treasury yields to assess equity attractiveness. When earnings yield is close to or below risk-free rates, equities may be expensive.
Why can P/E be misleading?
P/E is distorted by share buybacks (which reduce share count and inflate EPS), one-time items (which inflate or deflate reported earnings), high debt (which amplifies returns but also risk), and differences in accounting between companies. Always supplement P/E with other metrics: EV/EBITDA, P/FCF, Price-to-Book, and PEG ratio.