Does win rate matter? Why a high win rate can still lose money.
Win rate is the number strategies get sold on — “90% accuracy!” — and on its own it tells you almost nothing about whether you make money. A strategy that wins 9 trades in 10 can lose steadily, and one that's wrong most of the time can be highly profitable. What actually decides it is expectancy: how much you make on average per trade, once the size of the wins and losses is in the picture.
Expectancy = (win rate × average win) − (loss rate × average loss), measured in R — multiples of the amount you risked. Above zero, the edge is positive; below zero, more trades just lose you more. Win rate is only one of the three inputs.
Two strategies that break the intuition
Same idea, opposite lesson. These are worked illustrations, not live results — run the numbers yourself in the calculator.
You're right 9 times out of 10 — and still bleeding. Tiny profits taken quickly, the rare loss left to run. This is the shape of a martingale, or averaging down into a loser with no stop.
You're wrong nearly two times out of three — and profitable. Losers cut short, winners left to run. This is the shape of trend-following, which almost nobody can hold onto because being wrong that often feels awful.
Why win rate is the number you get sold
- • It feels like skill. Being right is satisfying; a high hit-rate is emotionally convincing in a way a payoff ratio never is — which is exactly why it's the headline on signal services and course ads.
- • It's the easiest number to inflate. Take profits early and refuse to cut losers and your win rate climbs — while your expectancy quietly goes negative. A “90% win rate” can be engineered; a positive expectancy that survives costs can't be faked as easily.
- • It hides the risk of ruin. A rule that wins small and loses big can post a lovely win rate right up until the one loss that takes the account. Win rate says nothing about how bad the bad days are.
None of this means a high win rate is bad — paired with a decent payoff it's excellent. It means win rate alone is not evidence of anything. Ask for the payoff ratio and the expectancy, and if a strategy is only ever sold on its win rate, treat that as a red flag.
Type in a win rate and an average win and loss to get the expectancy — or run a real backtest and read the win rate and the payoff together, the honest way.
The two strategies above are fixed, hand-verified illustrations of the arithmetic, not backtested results. R is the amount risked on a trade. This is an educational, analytical tool, not investment advice and not a recommendation to buy or sell anything. Hypothetical / simulated results, where shown, are not a reliable indicator of future results.