Convert betting odds between decimal, fractional and American formats, then check the raw implied probability and estimated stake return. Enter any one odds format and the calculator updates the rest automatically.
Use the converter below to compare odds formats, check implied probability and avoid reading a market price as a guaranteed prediction.
Use decimal odds above 1.00, fractional odds such as 10/11 or 3/2, American odds such as -110 or +150, or an implied probability percentage.
| Format | Conversion | Example |
|---|---|---|
| Decimal to probability | 100 ÷ decimal odds | 2.00 = 50.00% |
| Fractional to decimal | 1 + numerator ÷ denominator | 3/2 = 2.50 |
| Positive American to decimal | 1 + American ÷ 100 | +150 = 2.50 |
| Negative American to decimal | 1 + 100 ÷ absolute American odds | -200 = 1.50 |
| Decimal | Fractional | American | Implied probability |
|---|---|---|---|
| 1.50 | 1/2 | -200 | 66.67% |
| 1.91 | 10/11 approx. | -110 | 52.38% |
| 2.00 | 1/1 | +100 | 50.00% |
| 2.50 | 3/2 | +150 | 40.00% |
| 3.00 | 2/1 | +200 | 33.33% |
| 5.00 | 4/1 | +400 | 20.00% |
Implied probability is a pricing shortcut, not a guaranteed prediction. A decimal price of 2.00 implies 50.00%, but a real two-way market may price both sides above 50% once bookmaker margin is included. To judge whether a price is playable, compare the raw implied probability with your own fair probability and check the full market, not only one isolated price.
A single converted price tells you the raw probability of that selection, but it does not show the full margin in the market. In a balanced two-outcome market, two prices of 1.91 each convert to about 52.38% + 52.38% = 104.76%. The amount above 100% is the overround. That is why implied probability should be treated as a market price, not as a clean forecast.
Decimal odds are usually the simplest format because total return equals stake multiplied by decimal odds. Profit equals total return minus the original stake.
Yes. American odds of +150 convert to decimal odds of 2.50. A 100-unit stake would make 150 units profit and return 250 units total.
Negative American odds represent favourites. For example, -200 means a bettor would need to stake 200 units to make 100 units profit, which converts to decimal odds of 1.50.
This calculator shows raw implied probability from a single price. It does not remove bookmaker margin across all outcomes in a market, so the full market percentage may be above 100%.
Yes. The formulas are the same for pre-match and live odds. The important difference is that live odds can move quickly, so the converted probability may change within seconds.
