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Kelly Criterion Calculator

Calculate the mathematically optimal bet size based on your edge. Enter the market odds, your estimated fair odds, and your bankroll.

The odds offered by the sportsbook

Your estimated true odds (from your model or judgment)

How it works

The Kelly criterion calculates the mathematically optimal fraction of your bankroll to wager when you have an edge.

Formula: f* = (bp - q) / b

Where b = decimal odds - 1, p = your true probability, and q = 1 - p.

Half Kelly is generally recommended as it provides ~75% of the growth rate with significantly less variance.