A sportsbook is an establishment where people can place bets on a variety of sporting events. These bets are made against the odds set by the bookmaker. The odds determine how much a bettors can win if their prediction is correct. Sportsbooks offer a variety of betting options, including fractional odds (e.g. 3/1), decimal odds, and moneylines.

When a sportsbook sets its odds, it is attempting to attract evenly balanced action on both sides of the bet. This way, the sportsbook can earn money regardless of the outcome of a game. In practice, though, the flow is rarely perfectly even, and sportsbooks must adjust their lines for a variety of reasons. For example, injury or lineup news can significantly affect the expected result of a game. As a result, the sportsbooks will often move the line to reduce their risk by balancing the action or to take more bets from the public.

The goal of a retail sportsbook is to drive as much action as possible without sacrificing margins. However, this is a difficult balance to strike. Retail sportsbooks typically do so by taking protective measures like using relatively low betting limits, advertising on TV, offering loss rebates, promoting odds boosted markets, and sometimes limiting customers directly.