The myth: the win rate is the measure of a trader. 80–90% winners means you've made it; a method that loses most of its trades is a bad method. It's the first number beginners ask about, the number signal-sellers advertise, and the number that predicts almost nothing by itself.
The test: two simulated traders, identical 1% risk, identical costs, 400 trades, 4,000 runs each. Trader A wins 90% of the time — but the average winner is small (+0.15R) while the rare loser costs a full −1R. Trader B wins just 35% of the time, with +3R winners. Which account would you rather hold?
1% risk per trade, 400 trades, $10,000 start, identical per-trade costs.
The 90% trader loses money
Do the arithmetic the advertisement never does. Trader A: 0.90 × 0.15R − 0.10 × 1R = +0.035R per trade before costs — thinner than a typical cost load, so the median account bleeds. Trader B: 0.35 × 3R − 0.65 × 1R = +0.40R per trade — costs barely dent it, and the median account roughly doubles and keeps going. A win rate means nothing until it is multiplied by the size of wins and losses. The only number that pays is expectancy: (win% × avg win) − (loss% × avg loss).
The breakeven line every method must beat
Breakeven win% = 1 / (1 + R:R). Points above the line are profitable before costs; below it, no discipline can save the math.
This curve is the whole relationship on one line: at 1:1 reward-to-risk the bar is exactly 50% on paper, and above it in any real account once costs are paid; at 2R the bar drops to 33%; at 3R to 25%. High win rates aren't wrong — they are simply purchased, and the currency is reward size: to win very often you must take profits early and give losses room, which is exactly the 90%-trader's doomed geometry. Every method lives somewhere on this curve; the myth is believing the vertical axis is the score.
There's a psychological sting in the tail: the 90% system feels wonderful — months of nearly unbroken green — right up until the −1R days arrive in a cluster. The 35% system feels like constant failure while compounding steadily. The market pays the mathematics, not the mood. (This is also why the marketing of win rates works so well: it sells the feeling.)
Verdict
- Busted. Win rate alone predicts nothing; a 90% winner can be a net loser and a 35% winner a compounding machine.
- Expectancy is the score: (win% × avg win) − (loss% × avg loss). If a seller quotes a win rate without average win/loss, they are quoting decoration.
- Win rate and reward size trade against each other. Choose the combination that fits your psychology — then judge it only by expectancy.
- Know your breakeven line. At 2R winners, 33% is the bar. Everything above it, sustained across a real sample, is edge.