Expectancy Formula Explained

Most traders want to know whether a setup is “good.” Expectancy is the cleaner question.

Expectancy asks what a trading process is expected to make or lose per trade over a large enough sample, based on win rate, average win, average loss, and costs. It does not predict the next trade. It helps a trader audit whether the process has a math problem, a sizing problem, or an execution problem.

The simple formula

The basic expectancy formula is:

expectancy = (win rate × average win) - (loss rate × average loss)

If a trader wins 45% of trades with an average winner of $300 and loses 55% with an average loser of $180, the rough expectancy before costs is:

(0.45 × 300) - (0.55 × 180) = 135 - 99 = $36 per trade

That does not mean the next trade is worth $36. It means the historical or planned profile averages to that number before costs and slippage.

Why costs matter

Futures traders have commissions, exchange fees, spread, and slippage. If the strategy averages $36 before costs but gives up $18 per round trip, the review number changes fast.

The more a trader scalps, the more execution friction matters. A small target leaves less room for tiny mistakes. A strategy can look fine on a clean spreadsheet and weaker after real fills are included.

Expectancy is not a pass/fail button

Positive expectancy on paper is not enough. Prop firm accounts add drawdown limits, daily loss rules, consistency rules, and contract limits. A strategy can have a reasonable long-term profile and still be too volatile for the account boundary.

That is why expectancy belongs next to distance-to-bust and losing streak math. The useful question is not only “does the setup have an edge?” It is also “can this account survive the normal distribution of losses?”

Sample size traps

Five trades do not prove much. Ten trades can be noisy. Even 30 trades can hide a market-regime problem. Expectancy becomes more useful when the trader tracks the same setup type, under similar conditions, with planned risk and actual risk separated.

If the setup changes every session, the expectancy number becomes a blended story instead of a clean review tool.

A practical review workflow

Track these fields in a journal:

• ▸setup type
• ▸planned risk
• ▸actual risk
• ▸planned target
• ▸actual exit
• ▸fees and slippage estimate
• ▸rule context, including drawdown room and daily stop
• ▸behavior notes, especially revenge trades or size changes

Then review expectancy by setup, not just by week. A trader may discover one setup carries most of the quality while another setup adds noise.

Bucko workflow

Bucko fits this as an educational review workspace. Use it to keep the math, journal tags, account guardrails, and review notes in one place. The point is not to outsource decisions. The point is to make the trader-defined process easier to audit.

Expectancy is useful because it slows the story down. Instead of saying “I am good” after a green day or “I am broken” after a red day, the trader can ask what the numbers actually show.