Definition
Fractional odds show the profit a bet pays compared with the stake. In 5/1, the first number is profit and the second number is stake: a $1 stake wins $5 in profit.
Formula: profit = stake × numerator / denominator.
Total payout includes the original stake: total return = stake + profit.
Implied probability before sportsbook margin is: denominator / (numerator + denominator). For 5/1, that is 1 / (5 + 1) = 16.67%.
Worked Example
A $20 bet at 5/1 wins:
$20 × 5 / 1 = $100 profit.
The sportsbook returns the $20 stake plus $100 profit, so the total return is $120.
For a shorter price, 10/11 means a bettor risks $11 to win $10. A $110 bet at 10/11 wins $100 profit and returns $210 total.
Why It Matters
Fractional odds make payout size easy to audit before placing a bet. They help a bettor compare price, implied probability, and expected payout across sportsbooks or odds formats.