Expectancy, Win Rate, and Breakeven

The One Number That Tells You If Your Strategy Works

Win rate alone tells you almost nothing. A strategy that wins 70% of the time can still lose money. A strategy that wins 35% of the time can be highly profitable. The number that actually matters is expectancy — the average R multiple your strategy produces per trade, over a large enough sample to mean something.

The Expectancy Formula

Expectancy = (Win Rate x Average Win in R) - (Loss Rate x Average Loss in R)

Expressed per trade, in R. A positive expectancy means your strategy makes money on average over many trades, even though any individual trade can still lose. A negative expectancy means the opposite — even a strategy that "feels" good because it wins often can be quietly bleeding you.

Worked Example: High Win Rate, Negative Expectancy

Say a strategy wins 70% of trades, but winners average only +0.5R while losers average -1.5R (small, quick wins; a couple of stops that run further than usual).

Expectancy = (0.70 x 0.5) - (0.30 x 1.5)
Expectancy = 0.35 - 0.45
Expectancy = -0.10R per trade

This strategy loses money on average despite winning 70% of the time. Ten losing trades at -1.5R (-15R total) wipe out roughly 21 winning trades at +0.5R (+10.5R). The win rate feels great. The account shrinks anyway.

Worked Example: Lower Win Rate, Positive Expectancy

Now a strategy that wins only 40% of trades, but winners average +2R while losers average -1R.

Expectancy = (0.40 x 2) - (0.60 x 1)
Expectancy = 0.80 - 0.60
Expectancy = +0.20R per trade

This strategy loses more often than it wins, and still makes money over time, because winners are meaningfully larger than losers. This is the actual shape of most professional trading approaches: more losses than wins, but the wins pay for the losses with room to spare.

The Breakeven Win Rate

For any fixed reward-to-risk ratio, there's a minimum win rate needed just to break even (expectancy = 0). The formula:

Breakeven win rate = 1 / (1 + reward-to-risk ratio)

• At 1:1 (winners = losers in R): breakeven win rate = 1/(1+1) = 50%.
• At 2:1 (winners average 2x losers): breakeven win rate = 1/(1+2) = 33.3%.
• At 3:1: breakeven win rate = 1/(1+3) = 25%.

This is why traders who aim for 2R or 3R winners can be profitable while being wrong more often than they're right — the math allows it, as long as they actually let winners run to that ratio and cut losers at 1R.

Why This Changes How You Trade

If your setups realistically produce close to a 1:1 reward-to-risk, you need a genuinely high win rate — above 50% — just to survive, let alone profit. If that's not realistic for your setup, you have two choices: find setups with better structural reward-to-risk, or accept you need an edge in reading probability, not just direction.

Most durable trading edges lean on the second half of the equation — reward-to-risk — more than on being right often. It's far easier to consistently find setups with a clean 2:1 or 3:1 structure than it is to be right 65-70% of the time.

Turning This Into a Habit

Track, for at least 30 trades: win rate, average win in R, average loss in R. Calculate expectancy. If it's negative, don't try to "trade harder" — examine whether your losers are running bigger than your winners, whether you're cutting winners too early, or whether your stop placement (see the previous lesson) is structurally unsound. Expectancy is diagnostic. It tells you exactly where the leak is.

Takeaways

• Expectancy = (win rate x average win in R) - (loss rate x average loss in R); this single number, not win rate alone, tells you if a strategy is profitable.
• A high win rate can still mean negative expectancy if losers are disproportionately larger than winners.
• Breakeven win rate = 1 / (1 + reward-to-risk ratio) — at 2:1 reward-to-risk, you only need to win 33.3% of trades to break even.