Sports betting has exploded in America since the Supreme Court struck down the Professional and Amateur Sports Protection Act and allowed states to legalize it. There are now more than 20 states where wagering on professional and college sports is possible. In addition, online sites and apps hawked by celebrity sports figures are gaining popularity. But if you want to bet on sports, it is important to understand the risks involved.

Most bettors lose money on sports. The reason is simple: there are no bets made that are mathematically profitable on a regular basis. Those that are profitable, known as sharps, maintain profitability by carefully researching teams and events and using disciplined bankroll management. Even the sharpest bettors in the world will experience losses from time to time.

The majority of bets are on the outcome of a game or event, which are called spreads. The oddsmakers set the number of points or runs a team or player is expected to score or cover by taking bets on both sides of the point spread. The lower the spread, the more likely a team or player is to win. The higher the spread, the more difficult it is for a team or player to win.

Another popular bet type is the over/under, which is a prediction of the total number of runs or points scored in a game. The over/under number is calculated by adding the predicted total points and subtracting the actual total points. A high over/under number indicates a close game and a low over/under number means a low-scoring game.

Bettors also can make futures bets, which are bets on the outcome of a season or a championship. These bets are usually made before the season begins and payouts will be reduced as the season progresses, making them a bit like a stock option.

Unlike traditional gambling where the outcome is randomized, students of sports think they can sometimes predict what will happen and gain an edge over the bookmakers. Fans study statistics, listen to sports-related podcasts and get picks from trusted experts in the hope of gaining an advantage. These activities, along with the proliferation of betting ads on television and in digital form, feed this belief that sports can be predicted.

To increase your chances of winning, bet only on the sport(s) you know best from a rules perspective and use a good betting track record. It is also a good idea to avoid bets that feel impulsive or emotional. Getting hot after a few wins can lead to bad decisions and it is also wise not to chase your winners with more bets, which is called going on tilt. Also, be sure to keep your track of your bets by maintaining a spreadsheet and only betting with money you can afford to lose. And finally, bet sober – a few drinks can cloud your judgement and lead to bad decisions that could cost you your entire bankroll.