There are different ways that sportsbook can display their odds on an event. In the US, it is common to see American odds. In American odds, the favorite appears with a minus sign and the underdog with a plus sign. The numeral illustrates the extent to which a favorite is favored to win, or an underdog is expected to lose. American Betting Odds Calculator To illustrate, a slight favorite would carry odds of say -200, while a heavy favorite might be at -1500. Meaning you would need to wager $200 and $1500, respectively, to win $100. For a slight underdog at +200 or a heavy underdog at +1500, a $100 bet would return $200 and $1500, respectively. Stake$100Odds+200Return$300Winnings/Profit$200 ($300 return minus $100 stake) A simple betting calculator example to illustrate how american odds work Check out our short video explainer below with a few different examples for how to read American odds.