Multivariable Kelly Calculator
Consecutive Series:
Kelly Multiplier: Starting Bankroll:

After first betting set
Expected Profit: Expected Bankroll:
Expected Growth: Median Bankroll:

In probability theory, the Kelly criterion is a formula used to determine the optimal size of a series of bets. We use the Kelly formula as a base for all of our bet sizing. It is mathematically proven to provide the greatest rate of return while minimizing risk of ruin.





Let's say you're confronted with 8 bets on football sides at -110, all of which you expect to win 57% of the time, and you wanted to calculate the growth maximizing optimal bet sizes and expectations. You also wanted to determine both your expected and most likely bankroll after 13 weeks of similar betting opportunities. You start off with a bankroll of $1,000.

Set the event type selector to independent events, the # of events to "8", consecutive series to "13", starting bankroll to $1,000.00 (the two places after the decimal point will yield results to the nearest penny). The US Odds on all 8 bets would be -110 and the win probability would be 57%.

After clicking the "Calculate Kelly" button, you see that the optimal bet size for each of the 8 singles would be $47.49, for each of the 2-team parlays would be $5.10, for each of the 3-team parlays it would be $0.55, and for each of the 4-team parlays it would be $0.06.

At RLD Investments we never advise our clients to bet using parlays. We included them in the calculator as examples of how the Kelly criterion works only.

We see that this corresponds to expected profit of $70.51 and expected growth of $34.96. After repeating these bets each week over the course of our 13-week NFL betting season, you'd expect a bankroll of $2,424.91. Half the time your bankroll would be greater than $1,563.22, and half the time it would be less than $1,563.22.