Why a 90% Win Rate Can Still Lose Money
Expectancy and Trade Simulator
Reviewed 2026-07-31

Formula:
Expectancy = win rate x average win - loss rate x average loss - per-trade costs.

Checklist:
- Measure average win and average loss separately.
- Include commissions, spread, and slippage assumptions.
- Stress-test one or more maximum-loss events.
- Use expectancy and profit factor beside win rate.

Educational use only. Options involve risk and results depend on your assumptions.