Expectancy is the average amount you expect to win or lose on each trade over a large sample. It combines your win rate with your average win and loss sizes into a single number that tells you whether your trading strategy actually makes money. Expectancy is the single most important metric in trading because it answers the fundamental question: does your approach work?
How to Calculate Expectancy
Dollar-based formula
Expectancy = (Win Rate × Average Win) - (Loss Rate × Average Loss)
R-based formula (preferred)
Expectancy (R) = (Win Rate × Average R Win) - (Loss Rate × Average R Loss)
Where R = the amount risked per trade.
Example
- Win rate: 45%
- Average winner: 2.1R ($210 if risking $100)
- Average loser: 1.0R ($100)
Expectancy = (0.45 × 2.1R) - (0.55 × 1.0R) = 0.945R - 0.55R = 0.395R per trade
This means you earn an average of 0.395x your risk on every trade. If you risk $100 per trade, you expect to make $39.50 per trade on average.
Why Expectancy Matters
It combines win rate and R:R into one truth
Many traders obsess over win rate or R:R independently. Expectancy shows whether these two metrics work together to produce profit.
| Win Rate | Avg Win (R) | Avg Loss (R) | Expectancy (R) | Profitable? |
|---|---|---|---|---|
| 70% | 1.0 | 2.5 | -0.05 | No |
| 40% | 2.5 | 1.0 | +0.40 | Yes |
| 55% | 1.2 | 1.0 | +0.21 | Yes |
| 80% | 0.5 | 3.0 | -0.20 | No |
The 70% win rate trader is losing money. The 40% win rate trader is profitable. Only expectancy reveals this.
It tells you how much to trade
Once you know your expectancy, you can estimate your monthly income:
Expected Monthly Profit = Expectancy × Risk per Trade × Number of Trades
Example: 0.35R expectancy × $100 risk × 60 trades/month = $2,100/month
Positive vs. Negative Expectancy
- Positive expectancy (> 0): Your strategy makes money over a large sample of trades. Keep trading.
- Zero expectancy (= 0): You break even before costs. After spreads and commissions, you’re losing. Fix your strategy.
- Negative expectancy (< 0): Your strategy loses money. Stop trading it and analyze why.
Expectancy Traps
1. Small sample size
An expectancy calculated from 15 trades is statistically meaningless. You need 50+ trades minimum, preferably 100+.
2. Ignoring costs
Your expectancy needs to cover spreads, commissions, and swaps. A 0.05R expectancy might be positive before costs but negative after.
3. Regime dependency
An expectancy calculated during a trending market may not hold during a ranging market. Track expectancy across different conditions.
Tracking Expectancy in Your Journal
Your journal should calculate and track:
- Overall expectancy — Your aggregate expectancy across all trades
- Expectancy by pair — Which pairs give you the highest edge
- Expectancy by session — Where your edge is strongest
- Expectancy by strategy — Which setups are worth repeating
- Expectancy trend — Monthly expectancy plotted over time (is your edge improving or deteriorating?)
PipJournal calculates your expectancy automatically across every dimension and alerts you when your edge is deteriorating — before it becomes a serious problem.
