Market Margin Calculator
Calculate the bookmaker's margin (overround) on any betting market with 2 or more selections.
Bookmaker Margin
4.76%
Total Implied
104.76%
Fair Probabilities (No Margin):
The bookmaker keeps approximately 4.55% of every dollar wagered on this market.
What is Bookmaker Margin?
The bookmaker margin (also called overround, vig, or juice) is how sportsbooks guarantee profit. In a fair market, all implied probabilities sum to exactly 100%. Sportsbooks inflate these probabilities so they sum to more than 100%.
For example, a standard -110/-110 market has implied probabilities of 52.38% each, totaling 104.76%. The 4.76% over 100% is the margin. Lower margins mean better value for bettors.
Sharp sportsbooks typically have margins of 2-4% on main markets, while recreational books may have 6-10%+. Shopping for the best lines across multiple books helps minimize the margin you pay.
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Responsible Gambling
Gambling should be entertaining, not a way to make money. Only bet what you can afford to lose, and never chase your losses.
- Betting more than you can afford to lose
- Chasing losses with bigger bets
- Lying to others about gambling habits