A P/E ratio between 15 and 25 is often considered reasonable for a mature, profitable company, but there is no single number that works across every stock or sector. The price-to-earnings ratio divides a company’s stock price by its earnings per share, telling you how much investors are willing to pay for each dollar of profit. A “good” P/E depends entirely on what you’re comparing it to: the company’s industry, its growth rate, and the broader market environment.
What the P/E Ratio Actually Tells You
If a stock trades at $100 and earned $5 per share over the past year, its P/E ratio is 20. That means investors are paying $20 for every $1 of earnings. A lower P/E suggests the stock is cheaper relative to its profits, while a higher P/E suggests investors expect stronger future growth and are willing to pay a premium for it.
There are two versions you’ll see. A trailing P/E uses the last 12 months of actual earnings. A forward P/E uses analysts’ projected earnings for the next 12 months. Forward P/E is generally more useful for decision-making because you’re buying a stock for its future, not its past. But forward estimates can be wrong, so it helps to look at both.
P/E Ranges by Sector
Comparing a tech company’s P/E to a utility company’s P/E is like comparing the price of a sports car to a pickup truck. They serve different purposes, grow at different rates, and attract different buyers. As of January 2026, NYU Stern data from finance professor Aswath Damodaran shows just how wide the gap can be.
Utilities tend to have the lowest P/E ratios because they grow slowly and predictably. General utilities sit around 21, and water utilities near 22. Banks and insurers also cluster at the lower end: money center banks average about 17.6, and property and casualty insurers around 18.
Technology is a different story. Computer services companies average around 26, which looks modest until you see that semiconductor firms average about 70, and system and application software companies average over 122. Internet software companies sit above 160. These elevated numbers reflect the market pricing in years of expected earnings growth.
This means a P/E of 30 might look expensive for a utility company but cheap for a fast-growing software firm. The most useful comparison is always against other companies in the same industry.
How Growth Changes the Picture
A high P/E ratio is not automatically bad, and a low one is not automatically good. The missing piece is growth. A company trading at a P/E of 50 that’s growing earnings 50% per year may actually be a better deal than a company at a P/E of 15 with flat earnings.
This is where the PEG ratio helps. PEG stands for price/earnings-to-growth, and it divides the P/E ratio by the company’s expected annual earnings growth rate. A stock with a P/E of 30 and projected growth of 30% per year has a PEG of 1.0, meaning its price is roughly in line with its growth trajectory. A PEG below 1.0 suggests the stock may be undervalued relative to how fast it’s growing, while a PEG above 1.0 suggests investors might be overpaying for that growth. PEG is especially useful for evaluating growth stocks where the raw P/E looks alarmingly high.
When a Low P/E Is a Warning Sign
A stock with a P/E of 8 might seem like a bargain, but it can also be a trap. The market may be assigning a low price because it expects earnings to fall. Cyclical industries like oil, mining, and homebuilding often have their lowest P/E ratios right at the peak of a boom cycle, when earnings are temporarily inflated. When the cycle turns and earnings drop, the P/E spikes or becomes meaningless. Buying a cyclical stock because it looks cheap on a P/E basis is one of the most common mistakes investors make.
Companies carrying heavy debt loads can also produce misleading P/E ratios. Two firms with identical earnings per share might look equally valued on a P/E basis, but if one is loaded with debt and the other is debt-free, the risk profiles are very different. The P/E ratio ignores the balance sheet entirely.
One-time events distort the ratio too. If a company sold a division and booked a large gain, that quarter’s earnings will be unusually high, pushing the P/E artificially low. The reverse happens when a company takes a big write-down. Always check whether the earnings number behind a P/E reflects normal, ongoing operations.
A Practical Framework for Evaluating P/E
Rather than fixating on a single “good” number, use a layered approach:
- Compare within the industry. Look at the average P/E for the company’s specific sector. If peers trade at 25 and your stock trades at 15, dig into why. It could be a bargain, or the market could be flagging a problem you haven’t spotted yet.
- Check the growth rate. Calculate or look up the PEG ratio. A PEG near or below 1.0 suggests the price is reasonable relative to expected earnings growth.
- Look at the company’s own history. If a stock has traded between a P/E of 18 and 28 for the past decade and now sits at 35, that’s worth investigating. Something may have changed in the business, or the stock may simply be expensive.
- Use forward P/E alongside trailing P/E. A high trailing P/E combined with a much lower forward P/E usually means analysts expect a meaningful jump in earnings. If you trust those projections, the stock may be more reasonably priced than it first appears.
As a rough starting point, many value-oriented investors look for P/E ratios below 20 for established, slower-growth companies. Growth investors often accept P/E ratios of 30, 50, or higher when the company’s earnings are expanding fast enough to justify the premium. Neither approach is wrong. The P/E ratio is a starting point for analysis, not the final answer.