Guide overview
Learn how implied probabilities add up in a three-outcome market and why the total can exceed 100 percent.
Add the implied probabilities
For decimal prices, divide 1 by each price and add the results. If a hypothetical home, draw and away market is quoted at 2.00, 3.50 and 4.00, the implied shares are 50%, about 28.6% and 25%. Together they total about 103.6%, rather than 100%.
Why the total is above 100%
That excess is commonly called the overround or margin. It is a feature of the set of prices, not extra probability that belongs to any team. A simple proportional normalization can help compare the relative prices, but it does not reveal the true chance of an outcome or remove uncertainty.
Use comparisons carefully
A useful comparison checks the same fixture, the same settlement period and the same market definition. Prices may differ across operators, but a lower margin alone does not make a prediction accurate. Write down the calculation and assumptions so the percentage is not mistaken for a guaranteed edge.