Overround (Vig / Juice)
Overround — also called the vig, juice, or margin — is the percentage by which a bookmaker's implied probabilities sum to more than 100%. It is how books guarantee a profit over time, regardless of which way bets go.
How to calculate overround
Take the implied probability of every outcome in a market and add them up. The amount above 100% is the overround.
Example: a 1X2 market priced at 2.10 / 3.40 / 4.00 has implied probabilities of 47.6% + 29.4% + 25.0% = 102.0%. The 2.0% overround is the bookmaker's edge.
Typical overround by market
Asian books typically run 102–104% overround. European recreational books run 105–110%. US recreational books often run 115%+. Comparing odds across multiple books — and betting at the lowest-margin book per market — is the simplest sustainable edge any bettor can build.
Frequently asked questions
What does 5% overround mean?
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A 5% overround means the implied probabilities of all outcomes in a market sum to 105%. The bookmaker has built in a 5% margin across the market.