This Implied Probability Calculator converts American odds into implied probability. This calculation converts the odds into a form that is easier to quantify: percent likelihood of the event occurring. This type of calculator includes the sportsbooks margin, which means it isn’t the exact likelyhood. For a full description of the math behind the calculator see the article below. To use the implied probability calculator simply enter the American odd in the space provided and hit calculate to get the percent value.
How the Implied Probability Calculator works
Implied probability is most useful when determining the sportsbook’s edge over the bettor. It is important to note: this is not the margin/vig/juice. This is simply the advantage they have in being profitable over the bettor. Though it will never tell you which team to select, determining the percent implied probability over 100% will point out lines where the book’s advantage is lower. In being a successful sports betting every percentage point counts, and each point the book gives back is one more win toward profitability for the bettor.
Implied Probability Calculation for Negative American Odds
Calculating implied probability is a little more complex for American odds. Let’s take the classic coin flipping example where we know the actual probability is 50%: a -110 bet on Heads. Once again, the calculation is slightly different for for minus odds versus plus odds.
Implied Probability = (-1*(Odds)) / (-1(Odds) + 100)
Which looks like:
Implied Probability = (-1*(-110)) / (-1(-110) + 100)
52.4% or 0.524 = 110 / 210
That number should be familiar to experienced bettors as the break even winning percentage bettors shoot for. Because -110 on one side of a bet usually means -110 on the other side too, we can add all the probabilities (in this case another -110 probability) to determine the sportsbook’s edge.
(Heads Probability + Tails Probability) – 1 = Sportsbook’s Edge
(0.524 + 0.524) – 1 = 0.048 or 4.8%
Ideally you should be looking for bets with the lowest sportsbook edge you can. It is a subtle edge in sports betting, but remember the difference between winning at 52% and 53% is a world of difference.
Implied Probability Calculation for Positive American Odds
Let’s work a positive odds example. We’ll use the following moneyline bet where the favorite is -190 and the underdog is +160. First we break down the implied probability on +160 odds :
Implied Probability = 100 / (Odds + 100)
38.4% or 0.384 = 100 / (160 + 100)
To get the other outcome, we calculate the -190 odds:
65.5% or 0.655 = (-1(-190)) / (-1(-190) + 100)
In the above example we see that the sportsbook’s advantage is:
(0.384 + 0.655) – 1 = 3.9%
What this tells us is that with no other information a bet on the -190/+160 is more likely to be successful over the long term than the -110/-110 example.