Kelly Criterion Calculator

Find a full sports betting on what is the Kelly Criterion and how to use it in sports betting.

How to Use the Kelly Criterion Calculator

Using a Kelly Criterion Calculator, you’d provide the following information: 

• Your bankroll: The total amount you have to wager. 

• Odds format: American, Decimal, or Fractional. 

• Betting odds: The betting odds for the event. 

• Estimated Probability to Win: Put in the percentage chance you think you’ll win the bet. 

The formula for solving this is: (B x P - Q) / B

• B = Bet multiplier (net odds). Also viewed as Decimal odds -1.

• P = Probability of winning

• Q = Probability of losing 

Tip: For further assistance in assessing whether or not a bet has fair odds, you can use a “No Vig Calculator” to assess the fair win probability. This calculator will help you strip out the sportsbook’s margin. 

Real-World Kelly Criterion Calculator Example

Before using the Kelly Criterion Calculator, you may be sitting there wondering what percentage you should wager. Are you too conservative and only want to use something like 2% or 5%, or do you tend to be more overzealous and want to risk it all because “you know” a certain team is going to win?

We’ve all been there, but the Kelly Criterion Calculator is here to help find some middle ground. 

Of course, there will be times when even the best bets lose; that's a natural part of sports betting. 

With that said, let’s look at a real-world example: 

Let’s say a player has a $1,000 bankroll and is interested in betting on the Philadelphia Eagles moneyline of -110 against the Buffalo Bills. 

Now, let’s use the formula above: (B x P - Q) / B. 

• B = 0.91 because -110 converted to Decimal odds is 1.91, and 1.91 - 1 is 0.91. 

• P = Let’s say you think you have a 70% chance of winning. (0.70)

• Q = Thus, the probability of losing would be 30% (.30). 

So, the full equation in this example would be the following: 

• (0.91 × 0.70 – 0.30) / 0.91 = (0.637 – 0.30) / 0.91 ≈ 0.370

So, you’d use about 37% of your bankroll, which would be $370 of your $1,000 bankroll. 

It goes without saying, but when assessing your bankroll, only make it an amount that you’d be totally comfortable with completely losing. Never wager more than you can afford to lose. Don’t risk ruining your finances; treat sports betting as a fun recreational activity. See more about how to manage your bankroll.

Why Use a Kelly Criterion Calculator? 

Using a Kelly Criterion Calculator can have many benefits, including the following:

• Completely remove emotion from the betting decision to help maintain your bankroll and longevity. 

• Protects your bankroll by scaling your bets to what you have available. 

• Discourage you from making bad bets. 

Of course, nothing is the key to guaranteed winnings with gambling.

After all, there is a human element to this in assessing your confidence level. Over time, you’ll learn to refine your win probability estimates, and this tool should help you see a return over a long period of making wagers, not necessarily right off the bat.