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Implied probability is what the bookmaker's odds suggest the true probability of an outcome is. It includes the bookmaker's profit margin (vig), so implied probabilities always sum to more than 100% across a market.
Formula: Implied Probability = 1 ÷ Decimal Odds × 100
If you believe the true probability is higher than the implied probability, you have a value bet. Use our Expected Value Calculator to confirm.
Formula: Implied Probability = 1 ÷ Decimal Odds × 100
If you believe the true probability is higher than the implied probability, you have a value bet. Use our Expected Value Calculator to confirm.
Positive American (+200): Decimal = (American / 100) + 1 → (200/100)+1 = 3.00
Negative American (-150): Decimal = (100 / |American|) + 1 → (100/150)+1 = 1.667
Fractional (5/2): Decimal = (Numerator / Denominator) + 1 → (5/2)+1 = 3.50
Our calculator handles all conversions automatically — just enter any format and get all three instantly.
Negative American (-150): Decimal = (100 / |American|) + 1 → (100/150)+1 = 1.667
Fractional (5/2): Decimal = (Numerator / Denominator) + 1 → (5/2)+1 = 3.50
Our calculator handles all conversions automatically — just enter any format and get all three instantly.
The vig (vigorish) is the bookmaker's commission built into the odds. Because of the vig, the implied probabilities of all outcomes in a market always sum to more than 100%. The excess is the bookmaker's theoretical profit margin.
To find the true fair probability, you must remove the vig. Use our Vig Calculator to see the no-vig fair odds for any market. Then use those fair odds in this calculator to get the true probability.
To find the true fair probability, you must remove the vig. Use our Vig Calculator to see the no-vig fair odds for any market. Then use those fair odds in this calculator to get the true probability.