A sportsbook is a gambling establishment where people can place wagers on a variety of sports events. It was once an underground business but now, thanks to legalization and regulations, it is a legitimate source of revenue for many states. Understanding how to run a sportsbook can be a challenge, but the reward is substantial for those who succeed.

The most common type of bet is a straight bet, which is a wager on one team or player to win a game. In a straight bet, the sportsbook sets the odds by estimating the probability of an event occurring. The odds then reflect how much money bettors must risk in order to win a set amount.

Sportsbooks also set point-spread betting lines to balance action on both sides of a bet and reduce liabilities. This can be done when a line opens that induces lopsided action on one side, or when new information becomes available (injury, lineup changes, etc.). Additionally, a sportsbook will move the line when it believes its edge is too small and needs to balance action in order to make a profit.

Odds are a key tool in the sportsbook’s arsenal, and they vary based on the sport, event, and individual team. Most US-based sportsbooks use American odds, which display positive (+) or negative (-) numbers indicating how much money bettors can expect to win with a $100 bet. They also show the sportsbook’s vig, or house edge.