Odds express how likely an outcome is and, in betting, how much a winning bet pays. They can describe the chances of the player or of the house, and are sometimes shown as a percentage: two outcomes with a 50% chance each, for instance. Probability and price move in opposite directions. A bet on an outcome with a 5% chance pays far more than one with a 95% chance, which may not even double your stake.
Sportsbooks show odds in three main formats. With a stake of 100:
- Decimal (European), e.g. 1.40: total return is stake × odds, so 140.
- Fractional (British), e.g. 3/4: profit is three-quarters of the stake, so 75 profit and 175 back in total.
- American (moneyline), e.g. +200: profit on a 100 stake, so 200 profit and 300 back in total.
Bookmaker prices include a margin, so the implied chances in a market add up to more than 100%.