Free odds calculator
Odds Converter: American, Decimal and Fractional Odds
By DeepChamp research team · Updated · Methods and limitations
Short answer
Enter odds in any one format and the converter shows the same price as American, decimal and fractional odds, the implied probability, and the profit on your stake. All three formats describe one price; only the way the payout is written changes.
Odds converter
Include the sign: +150 or -110.
Used for profit and return.
| American odds | -110rounded to a whole price |
|---|---|
| Decimal odds | 1.909 |
| Fractional odds | 10/11closest simple fraction |
| Implied probability | 52.38%break-even win rate |
| Profit on a $100.00 stake | $90.91 |
| Total return if it wins | $190.91 |
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Researching a real market? Use the numbers in the app.
Download on the App StoreHow to use it
- 1Choose the format you have: American, decimal, fractional or implied probability.
- 2Type the number. American odds need a plus or minus sign, such as +150 or -110.
- 3Read the other formats, the implied probability and the profit and total return on your stake.
- 4Use the implied probability as the break-even point: the price only pays off over time if the outcome happens more often than that.
How the math works
American odds show how much you win on a 100 stake when the number is positive and how much you must risk to win 100 when it is negative. Decimal odds show the total return per one unit staked, including the stake. Fractional odds show profit relative to the stake, so 3/2 pays 3 for every 2 risked.
The implied probability is the break-even chance baked into the price. It is not the true chance of the outcome, because the price also contains the operator margin, which is why two sides of the same market usually add up to more than 100 percent.
- American to decimal (positive)
- decimal = 1 + odds / 100
- American to decimal (negative)
- decimal = 1 + 100 / |odds|
- Implied probability
- probability = 1 / decimal
- Fractional
- fraction = (decimal - 1), reduced
Common questions
How do you convert American odds to decimal odds?
For positive odds divide by 100 and add 1, so +150 becomes 2.50. For negative odds divide 100 by the absolute value and add 1, so -110 becomes 1.909. The decimal figure is your total return per one unit staked.
Why does -110 convert to 52.38 percent and not 50 percent?
At -110 you risk 110 to win 100, so you must win 110 of every 210 bets to break even, which is 52.38 percent. The extra 2.38 points over 50 percent is the margin built into the price.
Is implied probability the real chance of winning?
No. It is the break-even probability of the price after the operator margin. A fair estimate of the real chance has to come from your own research, and it can be higher or lower than the implied figure.
This is educational research content. Examples use hypothetical numbers and are not live odds, picks, or claims about performance.
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