Fractional odds
Fractional odds is a format used to display betting odds. The potential profit of a given bet relative to the risk is indicated by a reduced fraction. While fractional odds can be used to describe the odds of any betting market it is primarily used when discussing long odds such as futures.
How Fractional Odds Work
The betting odds are displayed as a reduced fraction. The potential profit of a given bet can be calculated by multiplying the fractional odds by the initial risk. In the example below the Los Angeles Lakers have 1/9 odds on the moneyline. Betting $300 would yield $100 profit for a total return of $400. This is calculated by multiplying the fractional odds (1/9) by the bet size ($300). The more favored a side is the smaller the fraction will be.
Team | Spread | Total | Moneyline | |
Los Angeles Lakers | -11.5 (10/11) | Over 217.5 (10/11) | 1/9 | |
Memphis Grizzlies | +11.5 (10/11) | Under 217.5 (10/11) | 6/1 |
Consequently the less favored a side of a betting market is the larger the fraction will be. In the same example the Memphis Grizzlies have 6/1 odds on the moneyline. A winning bet would turn the same $300 risk into $1,800 profit. The following table demonstrates the calculations necessary to determine the profit and total return for various fractional odds relative to a fixed $100 stake:
Fractional Odds | Risk | Profit Calculation | Return Calculation |
1/4 | $100 | $100 x 1/4 = $25 | $25 + $100 = $125 |
1/2 | $100 | $100 x 1/2 = $50 | $50 + $100 = $150 |
10/11 | $100 | $100 x 10/11 = $91 | $91 + $100 = $191 |
1/1 | $100 | $100 x 1/1 = $100 | $$100 + $100 = $200 |
2/1 | $100 | $100 x 2/1 = $200 | $200 + $100 = $300 |
5/1 | $100 | $100 x 5/1 = $500 | $500 + $100 = $600 |
10/1 | $100 | $100 x 10/1 = $1,000 | $1,000 + $100 = $1,110 |
25/1 | $100 | $100 x 25/1 = $2,500 | $2,500 + $100 = $2,600 |
A wager with a 1-to-1 return would have 1/1 fractional odds as a $100 risk would net a $100 profit. However two sides of a betting market with equal fractional odds will likely be set at 10/11. This is due to the bookmaker's commission.
Fractional odds are primarily used when discussing long odds such as large underdogs or futures. American odds or decimal odds are preferred when discussing shorter odds. Smaller fractions can be difficult to visualize. It is easier to interpret -205 or 1.49 in conversation instead of 21/43. On the other hand it's easier to reference a team's 50/1 championship odds rather than saying +5000 or 51.00.