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Position Math

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Expectancy Calculator

Turn your measured win rate and average win/loss into per-trade expectancy, profit factor and the break-even win rate your payoff needs.

Trading expectancy estimates the average result per trade from your win rate, average win and average loss: E = p x W - (1 - p) x L, while profit factor compares gross wins to gross losses and break-even win rate shows the win rate your payoff ratio needs.

Trade statistics

E = p·W − (1−p)·L · PF = (p·W) / ((1−p)·L)

Edge readout

Expectancy per trade—
Reward : risk—
Expectancy in R—
Break-even win rate—
Profit factor—
Enter your measured win rate and average win/loss.

How it works

What this calculator does

Expectancy is the average result a strategy would produce per trade if the same edge repeats over many trades. It combines how often you win with how large the average win is compared with the average loss.

The formulas

E = p × W − (1 − p) × L

RR = W / L

expectancy in R = p × RR − (1 − p)

break-even win rate = 1 / (1 + RR)

profit factor = (p × W) / ((1 − p) × L)

Worked example

A strategy that wins 40% of the time, makes 2 units on an average winner, and loses 1 unit on an average loser has 0.40 × 2 − 0.60 × 1 = 0.20 units of expectancy per trade. Its payoff is 2:1, so it only needs a 33.33% win rate to break even before costs.

What it deliberately does not do

It does not estimate your real win rate for you. Use a clean sample from your own journal, then treat the output as a model estimate from those inputs. Costs, slippage, changing market regimes and execution mistakes can all move realized results away from the arithmetic.

Frequently asked questions

What is trading expectancy?
Trading expectancy is the average profit or loss per trade implied by your win rate, average win and average loss. A positive number means the inputs describe a positive-edge sample before any costs you have not entered.
How do I calculate expectancy?
Use E = p × W − (1 − p) × L, where p is win rate, W is average win, and L is average loss as a positive magnitude.
What is expectancy in R?
Expectancy in R divides the average win by the average loss first, then expresses the result in units of risk: p × RR − (1 − p). It lets you compare systems with different dollar sizes.
What profit factor is good?
Profit factor above 1 means gross wins exceed gross losses in the sample. Higher is better, but a small sample can make profit factor look cleaner than it really is.
Does positive expectancy mean the next trade should win?
No. Expectancy is an average over many trades, not a forecast for a single trade. Streaks and drawdowns still happen even when the long-run estimate is positive.

Related calculators

Risk / RewardPosition SizeLosing Streak

Funded-account checks

Use these three pages as a simple path: understand the rules, stress a scenario, then track consistency before a payout.

1Understand the ruleCompare challenge types, drawdown floors and payout logic.2Run a breach scenarioModel intraday vs end-of-day trailing drawdown before sizing a trade.3Track consistencyCheck whether one big day is blocking payout eligibility.
Information tool only. Every result is deterministic arithmetic (for the simulator, a probability estimate) from the numbers you enter. The calculators run in your browser with no account connection and nothing stored; the pairs scanner uses delayed, cached market data (daily figures, refreshed once a day), not a live feed. This is not investment, trading, tax, or financial advice — verify against your own broker or prop firm before acting.
Disclosure. Some outbound links may be affiliate or partner links; they never change how a tool computes.
Position Math · updated 2026-07-04 · all calculators
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Information tool only — not investment, trading, tax, or financial advice. All computation runs in your browser.