A sportsbook is a gambling establishment that accepts bets on various sporting events. Generally, these bets are placed on the outcome of a specific game or series of games. These bets are often made by individuals or groups of people. They can be placed at brick-and-mortar casinos and racetracks, or online. In the United States, legal sportsbooks are regulated by state laws and can only accept bets from gamblers located in states where sports betting is legal. In addition, online sportsbooks have to verify the identity of bettors through geo-location technology.

The main way a sportsbook makes money is by setting odds that ensure they will make a profit over the long term for each bet placed. The oddsmakers at a sportsbook determine which side of a bet will receive the most action by looking at how much money is being wagered on each side of a game or event. If they see too much action on one side, the sportsbook will adjust its odds to attract more action on the other side.

A sportsbook also sets odds on a variety of occurrences in each game, including the margin of victory and over/under totals. The latter bets are based on the sportsbook’s prediction of how many runs, goals, or points will be scored in the game. When a team has a higher probability of winning, the sportsbook will set its over/under lines lower. Conversely, if the team has a lower probability of winning, the sportsbook will raise its over/under lines.