Calculate the Kelly optimal stake for a bet with a known edge.
Kelly maximises long-run growth but produces uncomfortable volatility, and it recommends zero when there is no edge. Half Kelly gives three quarters of the growth with far smaller drawdowns. Kelly is acutely sensitive to probability estimation error, which is why practitioners use a fraction rather than the full figure.
Kelly Criterion
Kelly fraction = (probability × net odds − losing probability) ÷ net odds
These figures are estimates based on population-average formulas and are intended for training and recreational planning only. They are not medical advice. Consult a qualified health professional before starting or changing an exercise programme, particularly if you have an existing medical condition.
Kelly fraction = (probability × net odds − losing probability) ÷ net odds Kelly maximises long-run growth but produces uncomfortable volatility, and it recommends zero when there is no edge. Half Kelly gives three quarters of the growth with far smaller drawdowns.
Kelly is acutely sensitive to probability estimation error, which is why practitioners use a fraction rather than the full figure.
This calculator takes 4 inputs: Your estimated win probability, Decimal odds offered, Bankroll, Fraction of full Kelly to use. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.