Online sportsbooks also build a house edge into their betting lines. For example, you will normally find odds of -110 on either team covering the point spread on a football or basketball game.
That means you need to risk $110 to earn a $100 profit. If there were no house edge, you would only need to risk $100 to win $100.
The house edge on sports betting lines is also known as the juice, or the vigorish. The standard juice is 4.55%, which applies to odds of -110 on either side of a betting line.
Some sportsbooks take a lower house edge than average, which is known as reduced juice. For example, a betting site may offer -105 on either team to cover the spread. If you only need to risk $105 on either team to win $100, the house edge is just 2.46%.
It is important to shop around for the best odds when betting on sports, as that will boost your long-term chances of earning a profit.
You may also find some significant discrepancies in the odds offered by different sportsbooks on the same game. In some circumstances, you can cover one side of the bet at a certain sportsbook and the other side of the bet at a rival sportsbook, ensuring a profit irrespective of who wins. That is known as arbitrage.