What is expectancy?
Expectancy is the average modelled result per trade: win probability × average win, minus loss probability × average loss. A high win rate alone does not establish an edge; the size of losses matters too.
Enter the win and loss profile
Set Win rate, Average win in R and Average loss in R. Enter the loss magnitude as a positive number: use 1 for an average loss of −1R.
Set frequency and account risk
Enter Trades per month and Starting balance, then set Risk per trade. These connect the R-based model to approximate dollar outcomes.
Generate possible equity paths
Choose Simulated months and Simulation paths, then select Roll the probabilities. Compare the equity paths rather than relying on a single run.
Read the edge and break-even figures
Review expectancy per trade, expected R per month and break-even win rate. For an average win of 1.5R and average loss of 1R, the break-even win rate before costs is 40%.
A simple example
With 60% winners averaging 1.5R and 40% losers averaging 1R, expectancy is 0.60 × 1.5 − 0.40 × 1 = +0.50R per trade before costs. That average does not mean each trade, or each month, earns +0.50R.