Odds & Formats

Fractional Odds

An odds format expressed as a fraction (e.g., 5/2) showing profit relative to stake.

Also known as: British odds, UK odds, traditional odds

Definition

Fractional odds express profit relative to stake. At 5/2, you win $5 profit for every $2 staked. The total return is $7 (profit + stake).

Fractional odds are the traditional format in UK and Irish betting, especially horse racing. 'Evens' (1/1) is even money. Anything below 1/1 (like 1/2) is odds-on (a favorite).

To convert to decimal: divide the fraction and add 1. So 5/2 = 2.5 + 1 = 3.50 decimal.

Formula

decimalOdds = (numerator / denominator) + 1
profit = stake × (numerator / denominator)

Worked Example

At 5/2: a £10 bet profits £25, with a total return of £35. Implied probability = 2/(5+2) = 28.6%.

Try It Yourself

Odds Converter

Convert between American, Decimal, Fractional and Implied Probability

Related Terms

American Odds

An odds format where negative numbers show how much to risk for $100 profit, and positive numbers show profit on a $100 bet.

Decimal Odds

An odds format showing total return per unit staked. Decimal 2.50 means $2.50 back per $1 bet.

Implied Probability

The probability of an outcome implied by the odds. Includes the bookmaker's margin (vig).