Probabilities for traders

Edge Simulator

Explore how win rate, average win, average loss, trade frequency, and position size combine into positive or negative expectancy.

Edge status Positive edge +0.50R expectancy per trade
+0.50Rexpectancy / trade
+5.00Rexpected R / month
+$5,000expected $ / month
40.0%break-even win rate

Readout

This setup has positive expectancy. The question is whether you can execute enough trades for the math to show up.

Strategy comparison

Simulated equity paths

Example strategies, translated into R

10 trades per month · 1R loss baseline

How to read it

  1. Expectancy is the average R you expect per trade: win probability times average win, minus loss probability times average loss.
  2. Break-even win rate shows how often you need to win for this payoff profile to stop losing before costs.
  3. Position sizing changes the dollar swing, not the edge. Too much size can wreck a good system before the probabilities get time to work.
  4. Entries and exits matter because they change both the number of winners and how big those winners are.