What Is Vig in Sports Betting?
Ever wondered how sportsbooks make money when they don’t know which team will win? Whether you’re betting on an NBA point spread, an MLB moneyline or a Premier League match, part of the answer is vig.
Short for vigorish, vig is the margin sportsbooks build into their betting odds. You’ll also hear it called juice or margin, and unlike a traditional fee, it isn’t something you pay separately. Instead, it’s reflected in the price you’re offered.
How Does Vig Work?
Imagine the New York Yankees are playing the Boston Red Sox, and both teams have exactly a 50% chance of winning. With no sportsbook margin, the fair odds would be +100 on either team, meaning a $100 bet would earn $100 in profit.
Instead, let’s say the sportsbook offers -110 on both teams. Now you need to risk $110 to win $100. If two customers each bet $110 on opposite teams, the sportsbook collects $220 and pays $210 to the winner, including the returned stake. The remaining $10 is its margin.
That’s essentially how vig works. The sportsbook offers slightly less generous odds than the fair price, creating a mathematical advantage for itself. Real sportsbooks don’t always receive equal amounts on both sides, though, so they aren’t guaranteed to profit on every game.
How Much Does Vig Cost You?
Let’s say you place 100 NBA spread bets at -110 odds, risking $110 each time. You win 50 and lose 50, which might sound like a respectable record. Unfortunately, you’d still be down $500 because your winners earned $5,000 while your losers cost $5,500.
To break even at -110, you actually need to win approximately 52.38% of your wagers. And as the odds become less favorable, that percentage increases.
| Betting odds | Profit on $100 | Break-even win rate |
|---|---|---|
| +150 | $150.00 | 40.00% |
| +100 | $100.00 | 50.00% |
| -105 | $95.24 | 51.22% |
| -110 | $90.91 | 52.38% |
| -120 | $83.33 | 54.55% |
| -150 | $66.67 | 60.00% |
These are break-even percentages rather than the vig itself. Still, they show why your win rate only tells part of the story. Two bettors can predict the same number of games correctly and end up with very different results simply because they accepted different odds.
How Do You Calculate Vig?
Every betting price represents an implied probability, which is the percentage of bets you’d need to win to break even at those odds. When you add the implied probabilities for every possible outcome, the total will usually exceed 100%. That extra percentage is called the overround, a common measure of the sportsbook’s margin.
Let’s use an NHL moneyline as an example:
| Team | Odds | Implied probability |
|---|---|---|
| New York Rangers | -150 | 60.00% |
| Boston Bruins | +130 | 43.48% |
| Total | 103.48% |
Because only one team can win this two-outcome market, the actual probabilities must add up to 100%. The additional 3.48 percentage points represent the overround.
For soccer’s traditional three-way moneyline, you’d include the home win, draw and away win in the calculation. The principle is the same, even though there are three possible outcomes instead of two.
Is Vig Different Between Sports?
Yes, although the betting market often matters more than the sport. Popular NFL and NBA spreads, along with major MLB and NHL moneylines, tend to attract substantial betting activity and can offer relatively competitive pricing. Player props, alternate lines and smaller markets may carry higher margins.
For example, an NBA player points market priced at -120 on both the over and under has an overround of approximately 9.09%, compared with 4.76% for a market priced at -110 on both sides.
Parlays introduce another consideration because the margin on individual selections can compound when you combine them. Same Game Parlays can be particularly difficult to evaluate because the outcomes may be related, such as an NBA team winning and its star player scoring 30 points.
None of this means you should automatically avoid certain markets. It simply means you should pay attention to the prices rather than assuming every bet is equally good value.
What Are No Vig Odds?
No vig odds are estimates of what the prices would look like without the sportsbook’s margin. They’re particularly useful when you’re trying to assess the expected value of a bet.
Remember our Rangers vs. Bruins example? The sportsbook offered -150 and +130, giving us a combined implied probability of 103.48%. Removing the margin using a simple proportional calculation produces estimated probabilities of approximately 58% for the Rangers and 42% for the Bruins, equivalent to odds of roughly -138 and +138.
These prices provide a useful reference point, but they aren’t guaranteed to represent the teams’ true chances of winning. Removing the vig doesn’t mean the sportsbook’s original assessment was correct.
How Can You Pay Less Vig?
The easiest approach is to compare prices before placing a bet. If one sportsbook offers an NBA spread at -110 and another has the identical spread at -105, the second gives you a better return for the same outcome.
Just make sure you’re comparing identical markets. An NBA total of over 224.5 points at -110 isn’t the same wager as over 225.5 at +100, and that extra point could be more important than the difference in odds.
You don’t need to calculate every sportsbook’s margin before betting. Simply understanding that vig exists, and that the price can vary between operators, will help you make better-informed decisions.
About the author
Senior Sports Betting Analyst
Dan Anderson is a Senior Sports Betting Analyst at Livesportsontv.com, specializing in NFL odds, bankroll management, and sportsbook promotions with over a decade of industry experience.
Dan Anderson
Senior Sports Betting Analyst