Calculate the mathematically optimal bet size based on your edge and bankroll. Supports full, half, and quarter Kelly.
The Kelly Criterion calculates the fraction of your bankroll to wager: f* = (p × b - q) / b, where p = win probability, q = 1-p, and b = decimal odds - 1.
Half Kelly is recommended by most professionals. It gives ~75% of the growth rate of full Kelly but with far less variance and drawdown risk.