Odds Converter
Enter odds in any format and instantly see the decimal, fractional, American and implied-probability equivalents.
Enter an odds value above to see the conversion.
Implied probability is the raw mathematical probability behind the price (1/decimal odds) and includes the bookmaker's margin (overround) — it is not the same as the true chance of the outcome.
Odds are written differently depending on where in the world you're betting. Swedish and most European sites use decimal odds, UK sites often use fractional (English) odds, and American sportsbooks use American (moneyline) odds. This odds converter switches between every format instantly, along with the implied probability behind each price.
The tool is especially useful when comparing odds across bookmakers, or when a site only shows a format you're not used to reading. Seeing all four formats side by side makes it much easier to judge whether a price is actually good value.
How the conversion works
Every conversion works internally from decimal odds. Whatever format you enter, it's first converted to decimal odds, which is then used to calculate the other formats using the formulas below.
- Implied probability: p = 1 / decimal odds. Decimal odds of 2.50 give an implied probability of 1/2.50 = 40%.
- American odds: if decimal odds ≥ 2.00, American odds = (decimal odds − 1) × 100. If decimal odds < 2.00, American odds = −100 / (decimal odds − 1).
- Fractional (UK) odds: decimal odds − 1 expressed as a reduced fraction. Decimal odds of 2.50 becomes 1.50, which is 3/2.
Worked example
Say a bookmaker offers decimal odds of 2.50 on a win. The implied probability is 1/2.50 = 0.40, or 40%. Since decimal odds ≥ 2.00, American odds work out to (2.50 − 1) × 100 = +150. The fraction is (2.50 − 1) = 1.50, reduced to 3/2 in fractional format.
Another example: decimal odds of 1.50 on a clear favourite. Implied probability is 1/1.50 ≈ 66.7%. Since decimal odds < 2.00, American odds are −100 / (1.50 − 1) = −200, and the fraction 0.50 reduces to 1/2.
Frequently asked questions
What does implied probability mean in odds?
Implied probability is the probability an odds price mathematically represents, calculated as 1 divided by the decimal odds. It includes the bookmaker's margin (overround), though, so the probabilities across every outcome in a market always add up to more than 100%. That means implied probability is always a little higher than the bookmaker's true assessment of the chance.
Why do American odds differ between plus and minus?
Positive American odds (e.g. +150) show how much you win on a 100 stake, and are used for underdogs (decimal odds of 2.00 or higher). Negative American odds (e.g. −200) show how much you must stake to win 100, and are used for favourites (decimal odds under 2.00). At exactly even odds (decimal odds 2.00), both +100 and −100 represent the same price.
Are fractional (UK) odds and decimal odds the same thing?
No, but they describe the same price in different ways. Fractional odds show only the profit relative to the stake (e.g. 3/2 means you win 3 for every 2 staked), while decimal odds show the total payout including the stake (3/2 is equivalent to decimal odds of 2.50). To go from fractional to decimal, add 1 after dividing: 3/2 + 1 = 2.50.
