The traditional UK odds format, expressing profit relative to stake as a fraction — 3/1 means £3 profit for every £1 staked.
Fractional odds show your profit per unit staked. 5/1 (read "five to one") means for every £1 you stake, you win £5 profit (plus your £1 stake returned) = £6 total. Evens (1/1) means you win exactly what you stake. 1/2 (read "one to two" or "odds-on") means you stake £2 to win £1 profit.
Fractional odds are still used by UK bookmakers for racing and some football markets, particularly ante-post. They have largely been replaced by decimal odds in digital betting interfaces, but remain common in betting shops and traditional printed racecards.
To convert fractional to decimal: (numerator ÷ denominator) + 1. 9/2 → (9÷2) + 1 = 4.50 decimal. To get implied probability: denominator ÷ (numerator + denominator). 9/2 → 2 ÷ (9+2) = 18.2% implied probability. Evens (1/1) → 50% implied probability.
Decimal Odds
The standard odds format in Europe and on exchanges, expressing total return per unit staked — including the return of the stake itself.
American Odds (Moneyline)
The US betting format: positive odds show profit on a £100 stake; negative odds show the stake required to profit £100.
Implied Probability
The probability of an outcome embedded in bookmaker odds — calculated by dividing 1 by the decimal odds.
For informational and educational purposes only. Disclaimer
