Trading Expectancy: The Only Formula That Matters

What is expectancy?

Any single trade is mostly noise — you can do everything right and lose. Expectancy looks past the noise to ask: across a large number of trades, what does the average one return? That average, not any individual outcome, is what actually grows or shrinks an account.

It is the number that decides whether a strategy is worth trading. A method with positive expectancy makes money if you repeat it enough times; a method with negative expectancy loses, however exciting its winners look.

The formula

Expectancy per trade is:

(win rate × average win) − (loss rate × average loss).

Say you win 40% of trades, your average win is $200 and your average loss is $100. Expectancy = (0.40 × 200) − (0.60 × 100) = 80 − 60 = +$20 per trade. Over 500 trades that is roughly $10,000 of edge, entirely independent of any single result.

Expectancy in R

Dollars depend on size, so professionals express expectancy in R. If your average win is 2R and average loss is 1R at a 40% win rate: expectancy = (0.40 × 2) − (0.60 × 1) = 0.8 − 0.6 = +0.2R per trade.

Now the number is portable: +0.2R means you make, on average, one fifth of your risk per trade whatever the account size. Multiply by how many trades you take and by your risk per trade, and you have a realistic picture of returns.

Why expectancy beats win rate

Win rate on its own is a vanity metric. A 90% win rate is a losing strategy if the occasional loss is ten times the size of each win. A 35% win rate is a great strategy if winners are three times the losers. Expectancy is what exposes this, because it weighs frequency and size together.

Chasing a high win rate often quietly destroys expectancy — traders cut winners early and let losers run to “be right.” The goal was never to be right often; it was to be net positive.

How to improve expectancy

There are only three levers: raise the win rate, raise the average win, or cut the average loss. The most reliable is the last — keeping losses at or below 1R by honouring your stop — because it is fully within your control, while win rate is not.

Letting winners reach their targets and refusing to let losers exceed 1R does more for most traders than any new setup. Small, consistent improvements to average loss compound hard over hundreds of trades.

Measuring your own expectancy

You cannot manage what you do not measure. Record every trade's R result in a journal, then average them: the mean R is your expectancy. A sample of at least 30–50 trades starts to be meaningful; a handful tells you nothing.

The free calculators on this site let you stress-test an expectancy against realistic losing streaks. Know your number, trade it consistently, and let the sample size do the work.

Frequently Asked Questions

What is trading expectancy?

Expectancy is the average profit or loss you can expect per trade over many trades. It is calculated as (win rate × average win) − (loss rate × average loss). A positive expectancy means the strategy has an edge.

How do you calculate expectancy?

Multiply your win rate by your average win, then subtract your loss rate multiplied by your average loss. Expressed in R-multiples, for example a 40% win rate with 2R wins and 1R losses gives +0.2R per trade.

Why is expectancy more important than win rate?

Because win rate ignores the size of wins and losses. A high win rate loses money if losses are far larger than wins. Expectancy weighs frequency and size together, so it reflects whether you actually make money.

What is a good expectancy?

Any positive expectancy is an edge. Even +0.2R per trade compounds meaningfully over hundreds of trades. The number matters less than being reliably positive and trading a large enough sample.

How many trades do I need to measure expectancy?

At least 30 to 50 trades before the average becomes meaningful, and more is better. A handful of trades is dominated by luck and tells you almost nothing about your true edge.