Finance Calc Kit

What is the price-to-earnings (P/E) ratio?

The price-to-earnings ratio is the most widely quoted equity valuation multiple. It shows how many dollars investors pay for each dollar of a company's earnings per share, or equivalently, how the entire market values the firm relative to net income.

Once you know P/E, adjust it for growth with the PEG ratio calculator, or compare revenue-based valuation using the price-to-sales ratio calculator when earnings are negative or volatile. For EPS, P/S, P/BV, and dividend ratios in one place, use the stock ratios calculator. To separate a stock price into no-growth value and growth opportunity (PVGO), use the PVGO calculator.

P/E ratio formulas

Per share, divide the current stock price by earnings per share (EPS). At the company level, divide market capitalization by net income:

\text{P/E} = \frac{\text{Share Price}}{\text{Earnings Per Share (EPS)}}

\text{P/E} = \frac{\text{Market Capitalization}}{\text{Net Income}}

When you have net income and shares outstanding, compute EPS first:

\text{EPS} = \frac{\text{Net Income}}{\text{Shares Outstanding}}

Worked example: $100 price and $5 EPS

A stock trading at $100 with EPS of $5.00 has a P/E of 20.00, meaning investors pay $20 for every $1 of annual earnings per share:

\text{P/E} = \frac{100}{5} = 20.00

Company-level calculation

A $1,000,000,000 market cap and $50,000,000 of net income also produce P/E 20.00. The detailed mode derives EPS from those figures before applying the per-share formula.

Trailing vs forward P/E

Trailing P/E uses the last four quarters of reported EPS. Forward P/E uses analyst consensus or your own forecast of next-twelve-months earnings. Forward multiples are more relevant for growth stocks but depend on forecast accuracy.

How to interpret P/E in practice

Low P/E: Can indicate a bargain, a cyclical trough, or a company with structural problems.
High P/E: Often reflects strong expected growth, high quality, or speculative momentum.
Compare peers: A P/E of 25 may be cheap for software and expensive for utilities.
Check earnings quality: One-time gains or losses can distort trailing EPS; normalize before trusting the multiple.

Frequently asked questions

What is a good P/E ratio?

The long-run U.S. market average trailing P/E has hovered near 15x to 20x, but sector norms differ sharply. Judge a stock against its industry, growth rate, and own history rather than a single benchmark.

What does a P/E of 20 mean?

At P/E 20, you pay $20 for every $1 of annual earnings per share. Equivalently, if earnings stayed flat and fully paid out, the implied earnings yield would be 5% (1 divided by 20).

Can P/E be negative?

Yes, when a company reports a net loss, EPS is negative and P/E loses its usual meaning. Analysts switch to P/S, EV/Revenue, or EV/EBITDA for unprofitable firms.

Trailing P/E vs forward P/E: which should I use?

Trailing P/E is objective because it uses reported results. Forward P/E is more predictive but depends on estimates. Many investors check both and note the gap between them.

How does P/E relate to the PEG ratio?

PEG divides P/E by the expected EPS growth rate (as a percentage). A P/E of 20 with 20% growth yields PEG 1.00, suggesting growth-adjusted fair value under the Peter Lynch framework.

Are my inputs saved on your servers?

No. All calculations run locally in your browser. Changing inputs updates the page URL so you can bookmark or share a specific scenario.

Resources and references

The formulas and methods in this calculator were checked against these independent sources.

Price To Earnings Calculator

Valuation inputs

How the P/E ratio is calculated