Odds formats explained
Sportsbooks around the world show odds in three main formats. Decimal odds are common in Europe, Canada, Australia and most online sportsbooks. Fractional odds are traditional in the United Kingdom and Ireland. American odds, also called moneyline odds, are used in the United States.
The format changes how a price looks, not what it is. Once you know the conversion rules, you can read any sportsbook with confidence and compare prices fairly. All examples below are illustrations of arithmetic, not tips.
Decimal odds
Decimal odds show the total return per 1 unit staked, including the stake. Odds of 2.50 return 2.50 for every 1 staked, so a 10 stake returns 25 and makes a profit of 15.
This is the easiest format for calculation. Total return = stake x decimal odds. To find the implied probability, divide 1 by the odds: 1 / 2.50 = 40%. For a combined bet, you multiply the decimal odds of each leg.
Fractional odds
Fractional odds show the profit relative to the stake. Odds of 3/2 (said as three-to-two) mean you profit 3 for every 2 staked. A stake of 10 would make a profit of 15 and return 25 in total.
To convert fractional to decimal, divide the top number by the bottom number and add 1. So 3/2 = 1.5, and 1.5 + 1 = 2.50. Evens is 1/1, which is decimal 2.00. Odds such as 1/2 are short: profit of 1 for every 2 staked, which is decimal 1.50.
A fraction where the top number is smaller than the bottom, such as 1/4, is called odds-on. It means the profit is less than the stake.
American (moneyline) odds
American odds use a plus or minus sign and a number, built around a 100 unit reference.
- A positive number such as +150 shows the profit on a 100 stake. A 100 stake at +150 makes a profit of 150.
- A negative number such as -200 shows how much you must stake to make a profit of 100. Staking 200 at -200 makes a profit of 100.
Positive odds are used for underdogs and negative odds for favourites. The scale jumps from -100 to +100 around evens, so there are no values between them.
Conversion formulas
Decimal is the common bridge between the other two formats.
- Fractional to decimal: decimal = 1 + (top / bottom).
- American positive (+X) to decimal: decimal = 1 + X / 100.
- American negative (-X) to decimal: decimal = 1 + 100 / X.
- Decimal to fractional: subtract 1 and write the result as a fraction, then simplify.
- Decimal to American: if decimal is 2.00 or more, American = (decimal - 1) x 100, shown with a plus sign. If decimal is below 2.00, American = -100 / (decimal - 1).
Worked examples
These examples are arithmetic illustrations, with decimal rounded to two places.
| Decimal | Fractional | American | Implied probability |
|---|---|---|---|
| 1.25 | 1/4 | -400 | 80.0% |
| 1.50 | 1/2 | -200 | 66.7% |
| 1.80 | 4/5 | -125 | 55.6% |
| 2.00 | 1/1 | +100 | 50.0% |
| 2.50 | 3/2 | +150 | 40.0% |
| 2.75 | 7/4 | +175 | 36.4% |
| 4.00 | 3/1 | +300 | 25.0% |
Check one row. American -125 means decimal = 1 + 100 / 125 = 1 + 0.80 = 1.80. The fractional form is 0.80 = 4/5. Implied probability is 1 / 1.80 = 55.6%. For +175, decimal = 1 + 175 / 100 = 2.75, and 1.75 simplifies to 7/4.
Choosing a format and checking your reading
Most sportsbooks let you change the format in account settings. Pick the one you read fastest, and stay with it so you are not tempted to misread a price. If you are unsure about a conversion, use the odds converter, which does the arithmetic for any of the three formats.
For the meaning of the price itself, read how betting odds work. To compare two sportsbooks fairly, convert both to decimal and compare. The higher decimal number pays more for the same bet, although the margin behind each price is explained in our bookmaker margin guide.
Rounding can hide small differences. The fractional 10/11 and the decimal 1.91 are almost the same price: 10/11 is 1.909, which rounds to 1.91.
Frequently asked questions
Which odds format is best?
None is better. They describe the same price. Decimal is the easiest for arithmetic, so many people convert to it when comparing prices.
How do I convert +200 to decimal?
Use decimal = 1 + X / 100. For +200 that is 1 + 2 = 3.00. A 10 stake returns 30 in total, with a profit of 20.
How do I convert -200 to decimal?
Use decimal = 1 + 100 / X. For -200 that is 1 + 0.5 = 1.50. A 10 stake returns 15 in total, with a profit of 5.
Does changing the format change the payout?
No. Switching the display only changes how the price is written. The payout depends on the price and your stake.