Edge. Every trader talks about it. Few can quantify it. Expectancy is the number that tells you exactly how much edge you have, expressed as dollars per trade. Positive expectancy means your strategy makes money over time. Negative expectancy means it loses money. Zero expectancy means you are paying commissions to break even.
This is the number that turns trading from a casino game into a business. When you know your expectancy, you know exactly how much each trade is worth on average. Multiply by the number of trades you take and you have your expected income. That is the foundation of every professional trading operation.
In This Article
What Is Expectancy
Expectancy is the average amount you expect to make or lose per trade over a large sample. It combines win rate and risk reward ratio into a single dollar figure that represents your edge.
A positive expectancy of $50 per trade does not mean every trade makes $50. Some trades win $500. Some lose $300. Some break even. But over hundreds of trades, the average outcome converges toward that $50. That is the law of large numbers working in your favour, but only if the expectancy is positive.
Calculating Your Expectancy
There are two common formulas. Both give you the same answer from different angles.
Method 1: The Direct Formula
Expectancy = (Win Rate × Average Win) - (Loss Rate × Average Loss)
Example: 45% win rate, $500 average win, $250 average loss.
Expectancy = (0.45 × $500) - (0.55 × $250) = $225 - $137.50 = $87.50 per trade
Method 2: The R Multiple Method
Express everything in terms of R (your risk per trade). If R = $200, and your average winner is 2.5R ($500) and your win rate is 45%:
Expectancy = (0.45 × 2.5R) - (0.55 × 1R) = 1.125R - 0.55R = 0.575R per trade
This means you expect to make 0.575 times your risk on each trade. At $200 risk, that is $115 per trade.
| Win Rate | Risk Reward | Expectancy per $100 Risk | Verdict |
|---|---|---|---|
| 30% | 3:1 | +$20 | Positive. Trend following style. |
| 45% | 2:1 | +$35 | Positive. Solid balanced strategy. |
| 55% | 1.5:1 | +$37.50 | Positive. Good mean reversion. |
| 70% | 0.8:1 | +$30 | Positive. High frequency scalping. |
| 50% | 1:1 | $0 | Breakeven. Add costs and you lose. |
| 60% | 0.5:1 | -$10 | Negative despite 60% win rate. |
What Edge Really Means
Edge is positive expectancy. That is the entire definition. If your expectancy is positive, you have an edge. If it is negative, you do not. Everything else is noise.
The size of your edge determines how aggressively you can trade. A $150 per trade expectancy allows much more aggressive position sizing than a $15 per trade expectancy. The thin edge is more fragile. Commission increases, slippage, or small changes in market conditions can flip it negative.
ACE Portfolio Tracker calculates expectancy automatically and shows you how it changes over time. A declining expectancy is an early warning sign that your edge may be fading. This is information you need before the drawdown tells you the same story in a more painful way.
Quantify Your Edge
See your expectancy per trade, per strategy, across every time period. Know exactly what your trading is worth.
Get Started FreeUsing Expectancy for Decisions
Position Sizing
Expectancy informs how much to risk per trade. Higher expectancy can support larger position sizes. Lower expectancy requires more conservative sizing. Combined with risk allocation strategies, expectancy becomes the basis for professional capital allocation.
Strategy Comparison
When comparing strategies, expectancy normalised per unit of risk (the R multiple method) gives you a level playing field. A strategy with $200 expectancy on $5,000 risk is less impressive than a strategy with $100 expectancy on $500 risk. Comparing strategies on expectancy per R makes this clear.
Know When to Stop
If your rolling 100 trade expectancy turns negative, your strategy has lost its edge. This is a clear, quantifiable signal that something has changed. Either the market has shifted, your execution has degraded, or the strategy needs adjustment.
Common Pitfalls
- Small sample sizes. Expectancy over 20 trades is meaningless. You need at least 100 trades for a reliable number, preferably 200 or more.
- Ignoring costs. Calculate expectancy after commissions, fees and slippage. A positive pre cost expectancy can easily be negative after costs.
- Static thinking. Expectancy changes over time. A strategy that had positive expectancy last year may have negative expectancy now. Track it continuously.
- Confusing expectancy with certainty. Positive expectancy does not mean every trade wins. It means the average over many trades is positive. You will still have losing streaks.
Build Your Portfolio Mission Control
Expectancy, profit factor, drawdown, Sharpe. All calculated automatically.
Start Free TrialRelated Articles
- Win Rate Explained for Traders
- Risk Reward Ratio Explained
- Profit Factor Explained
- Best Trading Metrics Every Trader Should Track
- How to Analyse Trading Strategies
- Risk Allocation Strategies