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Free Kelly criterion calculator
Kelly stakes the share of your bankroll equal to your edge divided by the price minus 1: (chance x price - 1) / (price - 1). With no edge it stakes nothing. Because the chance is an estimate, many bettors stake half or a quarter of the result. Enter the price, your chance and your bankroll below.
Kelly criterion calculator
How much of full Kelly?
Suggested stake
$45.45
Share of bankroll
4.55%
Full Kelly
4.55%
Full Kelly is 4.55% of the bankroll. Staking all of it gives 4.55%. Kelly assumes your chance of winning is right, and it is usually an estimate, which is why many bettors stake a half or a quarter.
18+. Arithmetic on the prices you enter, not a tip or a prediction. Prices can move, and bets can be limited or voided, before both are placed. Gambling Help Online: 1800 858 858.
The live version
BetBank picks shows positive EV bets with the edge on each, which is the input Kelly needs. The calculator turns the edge into a stake.
Worked example. Price 2.10, a 50% chance of winning, a $1,000 bankroll: (0.50 x 2.10 - 1) / (2.10 - 1) = 4.55% of the bankroll, a $45.45 stake. Half Kelly is 2.27%, $22.73. At 1.90 with the same 50% chance there is no edge, so the stake is $0.00.
What it assumes. That your chance of winning is right. Full Kelly maximises long-run growth only when it is, and it swings hard when it is not: an overestimated chance gives an oversized stake. It also treats each bet on its own and ignores bets that are open at the same time.
18+. These calculators do arithmetic on the numbers you enter; they are not tips or predictions. Gambling can be harmful. For free, confidential help call Gambling Help Online on 1800 858 858 or visit our responsible gambling page.
It is a formula for the stake that grows a bankroll fastest over many bets when you know your edge. The stake rises with the edge and falls as the price gets longer, and it is zero when there is no edge.
Full Kelly assumes your chance of winning is exact. It rarely is, so full Kelly tends to overbet, with large swings in the bankroll. A half or a quarter of Kelly gives up some growth for a smoother ride.
Your chance of winning is no higher than the price implies, so there is no edge to stake on. Kelly never stakes a negative amount: a negative result would mean backing the other side, which is a different bet.
Not directly. The formula sizes one bet at a time against the whole bankroll. If several bets are open together, staking each at full Kelly overbets overall, which is another reason to use a fraction.
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