What is the value of our calculator? The calculator shows the hidden margin that bookmakers include in their odds. When odds are entered, the calculator shows the ‘real’ or fair probability and fair odds for each outcome, removing the bookmaker’s margin. Bettors can instantly identify when the bookmaker’s odds are higher than the fair odds calculated by the tool. Such situations indicate the potential value bets, which are key to long-term profitability.
Enter the odds for each outcome. The calculator shows bookmaker's margin, implied, real probabilities and fair odds.
Margin = (1/Odds1 + 1/Odds2 + ... + 1/Oddsn) × 100 − 100
Example: Nottingham Forest - Brentfor (1x2)
William Hill odds: 2.2 − 3.4 − 3.1
Margin = (1/2.2 + 1/3.4 + 1/3.1) × 100 − 100 = 7.12%
As you know, bookmakers remain in profit regardless of the outcome of a sporting event. Why does this happen? The odds for an outcome are defined as the inverse of the probability of this outcome. For example, if the real odds on the outcome is 1.6, the probability will be equal to 1 / 1.6 * 100% = 62.5%. But the bookmaker includes their margin in this coefficient before the start of the sporting event. And the probability becomes – for example, 66.5%. These 4% (66.5% – 62.5%) represent the bookmaker’s margin. In practice, this means that the odds for the outcome which the bettor sees in the pre-match line will not be 1.6, but (1 / 66.5) × 100 ≈ 1.5.
A distinctive feature of the presence of a bookmaker’s margin is that the total probability of opposite outcomes, for example, over 1.5 goals and under 1.5 goals – will always add up to more than 100%.
