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Kelly Criterion: How to Use the Kelly Lab

The Kelly Criterion is a mathematical formula used to determine the optimal size of a series of bets. It is designed to maximize the logarithm of wealth, leading to long-term exponential growth.

The Formula

f* = (bp - q) / b
  • f*: The fraction of the bankroll to wager.
  • b: The decimal odds minus 1.
  • p: The probability of winning.
  • q: The probability of losing (1 - p).

The Importance of "Fractional Kelly"

Full Kelly can be extremely volatile. Most professionals use "Half-Kelly" (0.5) or "Quarter-Kelly" (0.25). This reduces the volatility significantly while still providing most of the growth benefits. You can adjust this multiplier in our **Kelly Lab** tool.

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