What is Odds?

Definition: Odds represent the sportsbook’s pricing of an outcome. They reflect the implied probability plus margin (overround), and they determine the potential payout.

Common formats:

Decimal Odds (e.g., 2.50) - payout = stake × odds (includes stake). Widely used in Europe.
Fractional Odds (e.g., 3/2) - profit relative to stake. Common in the UK/Ireland.
American Odds (e.g., +150 / -200) - shows profit on 100 units (+) or stake needed to win 100 units (-). Common in the US.

Implied probability (decimal) can be approximated as: 1 / decimal odds (before adjusting for margin).

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Related Terms

Implied Probability

Implied probability is the chance of an outcome expressed by the odds. It converts a price into a percentage.

Odds Formats (American, Decimal, Fractional)

Odds formats are different ways of writing the same price. A sportsbook front-end can display decimal, fractional or American odds depending on the market and player settings.

Fixed Odds

Fixed odds betting is a model where the price is agreed when the bet is placed. The payout is calculated from those odds, even if the market price changes later.

Wager (Stake)

A wager is a bet placed on an outcome. The stake is the amount of money committed to that bet. In everyday use the two words are often interchangeable.

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