Kelly Criterion Calculator
Enter your win rate and win/loss ratio. Returns full Kelly, half Kelly, and quarter Kelly fractions, with realistic drawdown estimates for each. Real-world convention is quarter Kelly because full-Kelly drawdowns regularly exceed 50% even when the math says you have an edge. Use this to size aggressively-but-honestly.
Read the lesson: The Kelly CriterionKelly Criterion Calculator
The mathematically optimal fraction to risk per trade - and why nobody trades full Kelly. Quarter Kelly is the working number for real strategies.
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- Position Size Calculator
How many shares or contracts to buy given your account size, per-trade risk, and stop distance.
- R-Multiple Calculator
Convert any trade outcome into R units. Lets you compare wins and losses across different position sizes on equal footing.
- Expectancy Calculator
What one trade is worth on average given your win rate, average winner, and average loser - and what 100 of them compound to.
- Drawdown Recovery Calculator
The asymmetry that ends careers: a 50% loss takes a 100% gain to recover. Visualised at any drawdown level.