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Sports betting odds come in three main formats — American (moneyline), decimal, and fractional — and all three express the same two things: how likely the sportsbook thinks an outcome is (implied probability) and how much you stand to win. American odds use plus and minus signs, decimal odds show your total return per dollar staked, and fractional odds show profit relative to your stake.
What are the three main sports betting odds formats?
The three standard formats are American, decimal, and fractional, and each is just a different way of writing the same underlying math. American odds (also called moneyline odds) are the default at most U.S.-facing offshore books. Decimal odds are common in Europe, Canada, and Australia. Fractional odds are traditional in the United Kingdom and Irish horse racing. Most sportsbooks, including Bovada and BetOnline, let you switch the display format in your account settings, so you can choose whichever feels most intuitive.
How do you read American (moneyline) odds?
American odds are built around a baseline of 100 units and use a plus or minus sign to show whether a side is an underdog or a favorite. A minus sign marks the favorite and tells you how much you’d need to stake to profit 100. A plus sign marks the underdog and tells you how much profit you’d make on a 100 stake.
- Example of a favorite: at -150, you would risk 150 to win 100 in profit (a 250 total return).
- Example of an underdog: at +150, you would risk 100 to win 150 in profit (a 250 total return).
These numbers scale to any stake — the 100 is just a reference point, not a required bet size. The bigger the minus number, the heavier the favorite; the bigger the plus number, the longer the underdog.
How do you read decimal odds?
Decimal odds show your total return per unit staked, including your original stake. To find your payout, multiply your stake by the decimal number. A figure of 2.00 represents an even-money bet, anything below 2.00 is a favorite, and anything above 2.00 is an underdog.
- At 2.50, a 100 stake returns 250 total (150 profit plus your 100 back).
- At 1.50, a 100 stake returns 150 total (50 profit plus your 100 back).
Many bettors find decimal the easiest format for comparing prices quickly, because a single number tells you everything and bigger always means a longer shot.
How do you read fractional odds?
Fractional odds show your profit relative to your stake, written as a fraction like 3/1 (“three to one”) or 1/2 (“one to two”). The first number is what you win; the second is what you stake. Unlike decimal odds, fractional odds do not include your returned stake in the figure.
- At 3/1, a 100 stake wins 300 in profit (400 total return).
- At 1/2, a 100 stake wins 50 in profit (150 total return).
When the left number is larger than the right, you’re looking at an underdog; when it’s smaller, you’re looking at a favorite. Fractions where both numbers are equal, such as 1/1, represent even money.
What is implied probability and how do you calculate it?
Implied probability is the chance of an outcome that the odds suggest, expressed as a percentage — and it’s the single most useful concept for evaluating value. “Value” simply means you believe the true probability is higher than the implied probability the odds are offering.
- From American favorites (minus): divide the odds by the odds plus 100. For -150, that’s 150 ÷ 250 = 60%.
- From American underdogs (plus): divide 100 by the odds plus 100. For +150, that’s 100 ÷ 250 = 40%.
- From decimal: divide 1 by the decimal number. For 2.50, that’s 1 ÷ 2.50 = 40%.
- From fractional: divide the stake by the sum of both numbers. For 3/1, that’s 1 ÷ 4 = 25%.
Comparing the implied probability baked into a price with your own estimate is the foundation of disciplined betting.
Why do the implied probabilities add up to more than 100%?
If you add the implied probabilities of both sides of a market, the total exceeds 100% — and that gap is the sportsbook’s built-in margin. This margin is called the “vig” or “juice” (short for vigorish), the commission a book charges for accepting your action. A common example is a market priced at -110 on both sides, where each side implies about 52.4%, totaling roughly 104.8%. That extra 4.8% is the house edge.
Because the vig varies from book to book, comparing prices across sportsbooks like BookMaker, MyBookie, and Everygame matters. Even a small difference in odds changes your long-run results, which is why many bettors hold accounts at several books. You can compare options on our best sportsbooks list.
How do you convert between odds formats?
Converting between formats is straightforward once you treat decimal as the hub. To go from American to decimal, a positive number becomes (odds ÷ 100) + 1, while a negative number becomes (100 ÷ odds) + 1. To go from decimal to fractional, subtract 1 and express the result as a fraction. Most sportsbooks handle this automatically through a display toggle, so you rarely need to do it by hand — but understanding the math helps you sanity-check what you’re seeing. Books such as SportsBetting.ag, GTBets, and BetUS typically support multiple display formats.
Which odds format should beginners use?
There’s no single “correct” format — the best one is whichever lets you read a price and grasp the payout instantly. Many U.S. bettors stick with American odds because that’s the default at offshore books like YouWager and BetNow, but plenty of bettors prefer decimal for how cleanly it expresses total return and probability. The smartest move is learning to read all three, so you’re never confused regardless of how a market is displayed.
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Frequently Asked Questions
What does a minus sign mean in betting odds?
A minus sign indicates the favorite — the side the sportsbook considers more likely to win. The number tells you how much you’d need to stake to earn 100 in profit, so -200 means risking 200 to win 100.
What does a plus sign mean in betting odds?
A plus sign indicates the underdog, the side considered less likely to win. The number shows how much profit you’d make on a 100 stake, so +200 means a 100 bet would return 200 in profit plus your original stake.
Are decimal and American odds different bets?
No. Decimal, American, and fractional are just different ways of displaying the exact same price and payout. A book may let you switch formats in your settings, but the underlying odds and your potential return do not change.
What is the vig in sports betting?
The vig, or juice, is the commission a sportsbook builds into its odds. It’s why the implied probabilities of both sides of a market add up to more than 100%, and it represents the house edge you’re paying to place a wager.
How do I know if odds offer good value?
Convert the odds into implied probability, then compare that percentage with your own estimate of how likely the outcome is. If you believe the true chance is higher than the implied probability, the data points to potential value on that side.