The vig, or juice, is the margin built into the odds. At the standard -110 on both sides, the implied probabilities add to 104.76 percent, not 100 percent. The extra 4.76 points is the overround, and on a balanced book it works out to a 4.55 percent hold. That is why a bettor has to win 52.38 percent of -110 bets just to break even, not 50 percent. In 2025, American sportsbooks held $16.96 billion of $166.94 billion wagered, a hold of about 10.2 percent.
The arithmetic of -110, and why 50 percent is not enough
Take the most common price in American sports betting: -110 on both sides of a game. Convert each side to an implied probability and you get 52.38 percent each, which adds to 104.76 percent. A fair market would add to 100 percent, because one side or the other has to win. The extra 4.76 points is the overround, the book's margin, and on a book with equal money on both sides it produces a hold of 4.55 percent. The book does not need to pick winners. It needs balanced action, and the overround pays it either way.
That is why the break-even point is 52.38 percent, not 50 percent. A bettor who wins half of their -110 bets is losing money, slowly and steadily, because every winning bet pays $100 on a $110 stake while every losing bet costs the full $110. The gap looks small on one bet and it is small on one bet. Over a hundred bets it is the difference between a hobby and a loss, and over a thousand it is the business model. Anyone selling a system that wins 51 percent of bets at -110 is selling a system that loses money.
Related reading on this site: Home and Why Sportsbooks Limit Winners: The Profile That Gets Your Stakes Cut cover the neighbouring problems in more depth.
The real hold is higher than the textbook number
The 4.55 percent figure assumes a balanced book on straight bets at -110. Real books hold far more. In 2025, American sportsbooks kept $16.96 billion of the $166.94 billion wagered, a hold of about 10.2 percent. Nevada held 7.45 percent of $8.07 billion wagered, and New Jersey held 9.7 percent of just over $12 billion. The gap between the textbook hold and the real hold comes from parlays, same-game parlays, and prop markets, where the margin is wider and the bettor's edge is thinner.
Parlays are where the vig multiplies. The margin on a two-leg parlay runs around 9 percent, on a three-leg parlay around 13 percent, and on a four-leg parlay around 17 percent, because the overround compounds with each leg. Illinois parlays held 18.3 percent in 2025. The book loves parlays for exactly this reason, and the marketing reflects it: parlay insurance, parlay boosts, and same-game parlay builders are the most promoted products on every app. A bettor who wants to beat the vig should start by understanding that the products pushed hardest are the ones with the widest margin.
How to see the vig before you bet
The vig is visible on every ticket, if you know where to look. Convert both sides of a market to implied probabilities and add them. A total near 100 percent means a thin margin and a fair price. A total over 105 percent means the book is taking a big cut, and a total over 110 percent means the market is barely worth betting. Shopping the same market across books is the simplest edge available, because the vig varies: one book may offer -110 while another offers -105 on the same game, and that five-cent difference is pure margin coming back to the bettor.
The second check is the parlay math. Before adding a leg, ask whether the extra leg is worth the extra margin it carries. A four-leg parlay at a 17 percent margin needs a much bigger edge to break even than four straight bets at 4.55 percent, and most bettors do not have that edge on any of the four legs. The vig does not make betting unwinnable. It makes it a game where the price matters as much as the pick, and the bettor who ignores the price is paying for the book's business whether they win or lose.
Frequently asked questions
What is the vig in sports betting?
It is the margin built into the odds. At -110 on both sides, the implied probabilities add to 104.76 percent, and the extra 4.76 points is the overround. On a balanced book that works out to a 4.55 percent hold.
What win rate do I need to break even at -110?
52.38 percent, not 50 percent. Every winning bet pays $100 on a $110 stake, so a bettor who wins half their bets is losing money over time.
How much do sportsbooks actually hold?
In 2025, American sportsbooks held $16.96 billion of $166.94 billion wagered, about 10.2 percent. Nevada held 7.45 percent of $8.07 billion, and New Jersey held 9.7 percent of just over $12 billion.
Why is the vig higher on parlays?
Because the overround compounds with each leg. The margin runs around 9 percent on a two-leg parlay, 13 percent on three legs, and 17 percent on four legs, and Illinois parlays held 18.3 percent in 2025.