The Math of Edge
How Low Win Rates Can Be Profitable
Win Rate Is Not Everything
Most beginners obsess over win rate. They think 80% wins = profitable. But that's only half the equation.
The Expectancy Formula
Expectancy = (Win% × Average Win) - (Loss% × Average Loss)
Real Examples
Trader A: High Win Rate, Low R:R
- •Win Rate: 70%
- •Average Win: 1R
- •Average Loss: 1R
- •Expectancy: (0.70 × 1) - (0.30 × 1) = +0.40R per trade
Trader B: Low Win Rate, High R:R
- •Win Rate: 30%
- •Average Win: 4R
- •Average Loss: 1R
- •Expectancy: (0.30 × 4) - (0.70 × 1) = +0.50R per trade
Trader B is MORE profitable despite winning less often.
The 100-Trade Proof
| Win Rate | R:R | Wins (of 100) | Gross Profit | Gross Loss | Net P&L |
|---|---|---|---|---|---|
| 30% | 1:4 | 30 | +120R | -70R | **+50R** |
| 40% | 1:3 | 40 | +120R | -60R | **+60R** |
| 50% | 1:2 | 50 | +100R | -50R | **+50R** |
| 60% | 1:1.5 | 60 | +90R | -40R | **+50R** |
Key Takeaway
All of these are profitable. The path you choose depends on your psychology and your entry model. High R:R traders lose more often but win bigger. High WR traders win more but make less per win.
Your Goal
After backtesting 100 trades:
- •Positive Expectancy = Your strategy has an edge
- •Negative Expectancy = Refine your rules and retest
"The math doesn't lie. Your feelings do. Trust the data."
Interactive Visual
Equity Curve Simulator
Win Rate30%
Risk:Reward1:4
100
Trades
30
Wins
70
Losses
+50R
Net P&L
(30 wins × 4R) − (70 losses × 1R) = +50R · Expectancy: +0.50R / trade
PROFITABLE EDGE: Even with a 30% win rate, the 1:4 R:R ratio creates positive expectancy. The order of wins is random, but the result over 100 trades is always 50R.
Knowledge Check
1/3Which trader has higher expectancy?