A sportsbook is a place where people can make bets on a variety of sporting events. These bets can be placed over the internet with a click of the mouse or tap of the screen. They can also be made by phone. For many years, the only legal sportsbooks in the United States were those operated in Nevada (and in limited form in Montana, Oregon and Delaware). A 2018 Supreme Court decision changed this and allowed states to license and operate their own sportsbooks.

All betting at sportsbooks revolves around the odds, which represent the probability of a particular outcome expressed as a price. Most U.S.-based sportsbooks use American odds, which display positive (+) and negative (-) numbers to indicate how much you could win with a $100 bet.

The odds of an event are constantly changing, and the sportsbook’s job is to balance out action on both sides by moving the line in a way that attracts or discourages certain types of bettors. For example, if one book is offering -180 on the Chicago Cubs and another is offering -190 on the Detroit Lions, the first book will move the line to encourage Cubs backers and discourage Lions bettors.

Before a bettor makes a bet at a sportsbook, they should read the sportsbook’s rules and policies. It is important to find a sportsbook that treats its customers fairly and offers adequate security measures. It is also important to do research on the sportsbook, including reading reviews. This will help a bettor determine which sportsbook is right for them.