Betting calculator
Odds Converter
Convert decimal, fractional and American odds, and see the implied probability behind each price.
Enter odds in any format
Type decimal odds, fractional odds or American odds. The other formats update automatically.
Decimal odds of 2.50 imply a 40.00% chance before bookmaker margin is considered.
What are betting odds?
Betting odds show the potential return from a bet and also imply the probability of that outcome happening. The same price can be shown in different formats depending on the bookmaker, exchange or country.
Decimal odds
Decimal odds show the total return for every £1 staked, including the original stake. For example, decimal odds of 2.50 mean a £10 stake would return £25 if the bet wins.
Total return = stake × decimal odds
Profit = total return − stake
Fractional odds
Fractional odds are common in the UK and Ireland. They show the profit compared with the stake. For example, odds of 3/2 mean you would win £3 profit for every £2 staked.
American odds
American odds are shown as either a positive or negative number. Positive American odds show how much profit you would make from a 100 unit stake. Negative American odds show how much you need to stake to make 100 units profit.
Implied probability
Implied probability converts odds into a percentage chance. With decimal odds, the formula is simple:
Implied probability = 1 ÷ decimal odds × 100
For example, decimal odds of 2.50 imply a 40% chance because 1 ÷ 2.50 × 100 = 40%.
Odds converter examples
| Decimal | Fractional | American | Implied probability |
|---|---|---|---|
| 2.00 | 1/1 | +100 | 50.00% |
| 2.50 | 3/2 | +150 | 40.00% |
| 1.50 | 1/2 | -200 | 66.67% |
| 4.00 | 3/1 | +300 | 25.00% |
Odds converter FAQs
Which odds format is best?
Decimal odds are often easiest for calculations because they show the total return including stake. Fractional odds are traditional in the UK, while American odds are common in the United States.
How do I convert fractional odds to decimal odds?
Divide the first number by the second number, then add 1. For example, 3/2 becomes 3 ÷ 2 + 1 = 2.50.
How do I convert decimal odds to implied probability?
Divide 1 by the decimal odds, then multiply by 100. For example, 2.00 becomes 1 ÷ 2.00 × 100 = 50%.
Do odds show the true chance of something happening?
Not necessarily. Odds show the price available in the market. Bookmaker margin, market opinion, liquidity and other factors can all affect the odds.