Convert between American, Decimal, and Fractional betting odds formats instantly
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To convert American odds to decimal: for positive odds, divide by 100 and add 1 (e.g., +150 = 2.50); for negative odds, divide 100 by the absolute value and add 1 (e.g., -200 = 1.50). To convert decimal to American: if decimal > 2, American = (decimal - 1) × 100; if decimal < 2, American = -100 / (decimal - 1).
American odds (also called moneyline odds) use positive and negative numbers. Positive odds (+150) show how much profit you make on a $100 bet. Negative odds (-200) show how much you need to bet to win $100. They're the standard format in US sportsbooks.
Fractional odds (e.g., 3/1, 1/2) show profit relative to stake. The first number is potential profit, the second is your stake. So 3/1 means you win $3 for every $1 bet. "Odds on" favorites show fractions less than 1 (like 1/2), meaning you risk more than you can win.
Different regions have historical preferences. American odds developed in US horse racing, fractional odds are traditional in UK/Ireland, and decimal odds became standard in Europe and Australia because they're easiest to calculate total returns. Most modern sportsbooks let you choose your preferred format.
Implied probability is the win probability that betting odds suggest. It's calculated as 1 / decimal odds. For -200 American (1.50 decimal), implied probability is 1/1.50 = 66.7%. This tells you what win rate you need to break even at those odds.
Decimal odds are best for quick calculations since you just multiply by stake to get total return. However, use whatever format your sportsbook displays to avoid conversion errors. Our converter helps you switch between formats instantly.