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Price-to-Earnings Ratio

P/E = Share Price ÷ Earnings Per Share

This number tells you how many dollars you pay for each dollar of company profit. A P/E of 20 means you pay $20 for every $1 the company earned.

01 Feel it first

Price divided by profit

Change the share price and the profit per share (EPS = profit ÷ number of shares). Watch the year blocks stack — each block is one year of today's profit it would take to match what you paid.

$150
$5$500
$6.00
-$4$40
Years of today's earnings to pay back the price
About 25 years of earnings to break even on price.
Price-to-Earnings
25.0×
$25.00 paid per $1 earned

At $150 a share earning $6.00, you pay 25.0× earnings. It would take about 25 yearsof today's earnings to earn back the price. A middle-of-the-road multiple, typical of a steady, established business.

02 Break the intuition

A $500 stock can be cheaper than a $50 one

A high share price does not mean an expensive stock. Guess which deal is better, then peel back the card to see the earnings.

COMPANY A
$500
per share
Earns per share$50.00
Price ÷ earnings500 ÷ 50
10.0×
Cheaper
COMPANY B
$50
per share
Earns per share$1.00
Price ÷ earnings50 ÷ 1
50.0×
5× pricier
The cheap-looking $50 stock is the expensive one. Company B costs $50 for every $1 of profit; Company A costs $10 for the same $1. Share price is just how big each slice is — it depends on how many shares exist. P/E tells you what you pay for the profit.

03 Predict it

Hit the target multiple

EPS is locked. Drag the price to land on a target P/E, then lock your guess and see how close you got.

EPS is fixed at $4.00. Where must the price sit for a 15× P/E?

$80
$10$250
Years of earnings (after lock)
Your implied P/E
20.0×
target 15×

Drag the price, then lock. We will reveal the price that hits 15× and score how close you got.

04 Find the fair zone

Drag the P/E across the bands

Scrub the P/E needle across cheap, fair, rich, and danger zones. The same multiple can look cheap for a bank and normal for software.

P/E
22.0×
Fair
22.0×
5.0×60.0×

At 22.0× you are in the Fair band. 30× can look expensive for a bank and normal for software. Always compare to peers.

05 Two flavors

Trailing vs forward

Same math, different profit number. One uses last year's real results. The other uses a guess about next year.

Uses the last 12 months of actual, reported profit (TTM = trailing twelve months). It is based on real numbers, but it is slow if the business is changing fast. Example: price $120 ÷ trailing EPS $4.00 = 30×.

06 The catch

A P/E only means something next to peers

30× can look expensive for a bank and normal for a fast-growing software company. Compare within the same industry, and against the company's own past.

Software
31×
Consumer
22×
Industrials
19×
Energy
13×
Banks
11×

Sample sector averages. Live sector numbers available on Amsflow.

07 Check yourself

Five quick checks

Question 1 of 5
Quick checkA stock trades at $80 and earned $2 per share last year. Its P/E is:
40× is right. P/E = price ÷ earnings per share = 80 ÷ 2 = 40.

08 Where it breaks

When P/E misleads you

Company is losing money

If profit is negative, P/E does not make sense. The math gives a negative or blank number. Many young growth companies sit here.

Boom-and-bust industries

Miners and carmakers can look "cheap" when profits are temporarily huge at the top of a cycle, and "expensive" when profits crash. P/E can flip the truth.

One-time accounting hits

Selling a building or writing down an asset can warp one year of EPS (earnings per share). The ratio then drifts away from normal earning power.

Ignores how fast profits grow

P/E alone does not care about growth. A 40× stock growing 30% a year can be a better deal than a 12× stock that is stuck. PEG adjusts for growth.

Stop reading about P/E. Go look at one.

See any of 70,000 stocks with live trailing and forward P/E, a 10-year history chart, and its sector average, side by side. Then screen the whole market by the ratio in one click.