How to use this calculator
- Choose a representative set of closed trades with wins and losses only.
- Enter the win rate and the positive magnitude of the average win and average loss before costs.
- Enter average round-trip costs across all trades. If your recorded outcomes are already net, set additional cost to zero to avoid double counting.
Formula and worked example
Net expectancy = win probability × average win − loss probability × average loss − average cost. Break-even win probability = (average loss + average cost) ÷ (average win + average loss).
With a 45% win rate, average win of 200, average loss of 100, and cost of 5, net expectancy is 0.45 × 200 − 0.55 × 100 − 5 = 30 per trade. The cost-adjusted break-even win rate is 105 ÷ 300 = 35%. All amounts must use the same currency.
What the result does—and does not—tell you
Expectancy is an average under the supplied two-outcome model. It does not describe the order of wins and losses, drawdown, uncertainty, or the likelihood of a particular next trade. Breakeven outcomes form a third category and are not modeled here. Excluding them changes the interpretation to expectancy per decisive trade. Changes in market conditions or trade selection can make historical averages unrepresentative.
Frequently asked questions
Does positive expectancy guarantee profit?
No. The result depends on the inputs and model. Actual outcomes, costs, and win probabilities can change, and losing sequences can occur even when a historical average is positive.
Can I use R-multiples instead of currency?
The displayed amounts are labeled account currency. For a normalized comparison, use the net expectancy divided by average loss output; this is not necessarily the same as expectancy in initial-risk R-multiples.
Why might break-even be impossible?
If the modeled average cost exceeds the average win, even a 100% win rate cannot break even. The tool reports the rate as not achievable rather than presenting a percentage above 100% as attainable.
Methodology and limitations
WTE Toolbox · Calculation model v1 · Updated September 6, 2026. These are deterministic calculations from manually supplied inputs. Examples are hypothetical, not recommended trades or risk limits. No market feed, account connection, or broker validation is used. Display values are rounded; calculations use unrounded intermediate values.
Educational use only, not personalized financial advice. Trading can result in substantial losses. A calculated stop loss is not a guaranteed execution price or maximum loss.