Kelly Criterion Calculator

Finding good bets is only half the job; sizing them is the other half. The Kelly Criterion computes the fraction of your bankroll to stake based on how big your edge is and how long the odds are. Enter the odds you are being offered and your fair win probability, and the calculator returns your expected value and the optimal bankroll percentage to wager.

Full Kelly is mathematically optimal but swings hard, so most bettors run a fraction of it. The multiplier field defaults to a quarter Kelly, a common choice that keeps variance manageable. If the bet has no edge, Kelly stakes zero: the formula will simply tell you not to bet, which is often the most profitable advice there is.