Expectancy

Updated 2026-09-20

Definition

The average gain per trade, usually measured in R: win percentage times average R won, minus loss percentage times average R lost.

Why it matters

A system is only interesting if it has positive expectancy over a large sample, with costs included. It's an average: in the short run long losing streaks can occur.

Practical example

40% wins at +2.5R and 60% losses at −1R: 0.4 × 2.5 − 0.6 × 1 = +0.4R per trade.

Learn more

Course lesson: Risk/reward and expectancy: the maths that tells you whether a system works

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Educational content, not financial advice. Trading involves risk.