Article
No-Vig Probability: How to Remove Sportsbook Margin
A transparent proportional normalization method for estimating fair probabilities from a complete sportsbook market.
Quick answer
For each outcome, compute 1/odds. Add those implied probabilities, then divide each one by the total. The normalized probabilities sum to 100%.
Step 1
Convert every outcome price to implied probability.
Step 2
Sum the probabilities to get the book percentage.
Step 3
Divide each raw implied probability by that book percentage.
Step 4
Convert the normalized probabilities back to fair decimal odds if useful.
Limitation
Proportional normalization assumes the displayed margin can be removed proportionally. More sophisticated models may distribute margin differently, especially in asymmetric markets.
Related reading
Responsible gambling: Gambling involves financial risk. Never chase losses or gamble with money needed for essentials. Eligibility and legal age vary by jurisdiction.