Required sample size calculator
Estimate how many trades your edge needs.
Calculator
Worked example
A strategy that wins less than half the time with winners about twice the size of its losers, tested at a common confidence level. These are the calculator's default inputs and the result it returns for them.
| Win rate | 40% |
|---|---|
| Average winner | 2 R |
| Average loser | 1 R |
| Confidence level | 95% |
| Sample required | 147 trades |
| Expectancy | +0.20R |
| Standard deviation | 1.47R |
A thinner edge needs more trades before luck stops dominating the result.
Questions
- What does the required sample size mean?
- It estimates how many trades you need before your average result stands clear of random noise at the chosen confidence level.
- How do I read the result?
- If you have fewer trades than the sample required, your results so far could still be mostly luck. A thinner edge or a wider spread of outcomes needs more trades.
- What is a common mistake?
- Treating the number as a finish line. It assumes each trade is independent and the market stays the same, so use it as a minimum.