Let’s consider a real-world example to understand how American odds work in action: A -250 favorite has a better chance of winning an event than a -150 favorite, while a +200 underdog has a better chance of winning than a +500 underdog. A minus sign indicates a bookie’s favorite to win while a plus symbol indicates an underdog. American odds start with either a positive or negative sign (e.g. This odds expression indicates a bettor’s return relative to a base figure of 100 units. You’re most likely to come across American odds when you’re betting at American sports betting sites. This isn’t as complicated as it might sound and, by the time you’ve read our guide to betting odds, you’ll be an expert. Different formats don’t mean different odds it’s simply a different way of presenting them. Betting odds may be displayed in three different formats at land-based sportsbooks, online betting sites, and mobile sports betting platforms: American odds, fractional odds and decimal odds. Betting odds simply indicate the likelihood of an event and the return you’d get if you did make a wager on the result. The first step to understanding betting odds is appreciating what they do. Odds Explained What are the Different Types of Betting Odds?