When it comes to betting on sports, there are many different options available. Some of these include moneylines, spreads, and parlays, as well as proposition bets which allow you to place a wager on more specific aspects of the game such as how many points a particular player will score. There are also many sites that offer both free and paid data services that can help you to make the best possible bets.

One of the most important concepts that any bettor should be aware of is expected value, or EV for short. This is calculated by comparing the actual probability of an event happening to the odds offered by the betting site. The greater the difference between these numbers, the more profitable a bet will be.

In addition to calculating EV, a bettor should also understand the margin that is charged by the bookmaker. This is known as the vig, and it’s often included in the odds. This is not a large amount of money, but it can add up over time if you’re losing a lot of bets.

Lastly, any bettor should be sure to track their ROI (return on investment) over time. This will allow them to identify betting value and avoid making bad bets. This is the only way to ensure long-term profitability. Always remember to set aside a percentage of your total bankroll for betting, and never bet more than you can afford to lose.