How to Read Betting Odds

American odds are written as a positive or negative number, like +150 or -110. Once you know what the sign means, the rest is short arithmetic.

Negative odds: the favoured side

A negative number is the side the book sees as more likely. It tells you how much you would stake to win 100 dollars. At -110 you stake 110 dollars to win 100, for a total return of 210 dollars if it hits. The bigger the negative number, the more you have to risk for the same 100.

Positive odds: the longer side

A positive number is the side the book sees as less likely. It tells you how much you would win on a 100 dollar stake. At +150 you stake 100 dollars to win 150, for a total return of 250 dollars if it hits. The bigger the positive number, the more it pays.

Turning a price into a probability

A price also carries an implied probability, the chance the number is built around. The formula differs by sign, and both are a single division.

Why both sides add up to more than 100

If a book prices both sides of a prop at -110, each side implies about 52.4 percent. Add them together and you get about 104.8 percent, more than a whole. That extra slice is the book's margin, often called the vig or the juice. It is why two prices are not a fair coin flip, and why the same prop can be a better deal at one book than another. Comparing those prices is what line shopping is about.

A quick reference

A few common prices and the probability each one implies, rounded:

• -200 is about 66.7 percent. Stake 200 to win 100.
• -150 is 60 percent. Stake 150 to win 100.
• -110 is about 52.4 percent. Stake 110 to win 100.
• +100 is 50 percent, an even bet. Stake 100 to win 100.
• +150 is 40 percent. Stake 100 to win 150.
• +200 is about 33.3 percent. Stake 100 to win 200.

Decimal and fractional odds

American odds are not the only format. Decimal odds show the total return on a 1 unit stake, so -110 is about 1.91 and +150 is 2.50. Fractional odds, common in the UK, show the profit as a fraction of the stake, so +150 is 3/2 and -200 is 1/2. They all describe the same thing; American is simply the format most US sportsbooks use, and the one you will see on this site.

One habit worth forming early: always read the price next to the line, not just the line itself. Two props at the same number can be very different bets once the odds are attached, and the price is half the information.