Odds Calculator
Convert between decimal, fractional, and American odds instantly. Calculate potential payouts, profit, and implied probability for any bet.
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Understanding Odds Formats
Decimal Odds
Decimal odds are the most straightforward format, popular in Europe and Australia. The number represents your total return per $1 staked (including your original stake).
Example: Odds of 2.50 mean a $10 bet returns $25 total ($15 profit + $10 stake).
Fractional Odds
Fractional odds are traditional in the UK and Ireland. They show profit relative to stake.
Example: Odds of 3/2 mean you win $3 for every $2 staked. A $10 bet profits $15.
American Odds
American odds use positive and negative numbers. Positive (+150) shows profit on a $100 stake. Negative (-200) shows how much to stake for $100 profit.
| Decimal | Fractional | American | Implied Prob. | Description |
|---|---|---|---|---|
| 1.50 | 1/2 | -200 | 66.7% | Strong favourite |
| 2.00 | 1/1 (Evens) | +100 | 50.0% | Even chance |
| 3.00 | 2/1 | +200 | 33.3% | Underdog |
| 5.00 | 4/1 | +400 | 20.0% | Long shot |
| 10.00 | 9/1 | +900 | 10.0% | Very unlikely |
What Is Implied Probability?
Implied probability converts odds into the percentage chance the bookmaker assigns to an outcome. The formula for decimal odds is: Implied Probability = (1 / Decimal Odds) x 100
If you believe the true probability of an outcome is higher than the implied probability, you have found a value bet — a bet where the odds are in your favour relative to the actual likelihood.
Bookmakers build a margin (overround) into their odds — the sum of implied probabilities for all outcomes exceeds 100%. A typical football match might sum to 105-110%. This margin is how bookmakers guarantee profit.