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Odds converter: decimal, American and fractional
Convert sports odds and calculate implied probability. A free educational calculator with formulas and examples, with no registration.
Local calculation. Your figures are not submitted or stored. Use a dot or comma for decimals, without thousands separators.
YOUR EXAMPLE
- Decimal odds
- 1.91
- American odds (rounded)
- -110
- Fractional odds (approximate)
- 91/100
- Implied probability
- 52.36%
How conversion works
Decimal odds include the original stake in the total return. Fractional odds describe net profit per unit staked. American odds use a positive or negative reference: +150 represents 150 of net profit for 100 staked; −150 represents 100 of net profit for 150 staked.
Decimal = 1 + fractional numerator / denominator
Implied probability = 100 / decimal odds
| Decimal | American | Fractional | Implied |
|---|---|---|---|
| 1.50 | −200 | 1/2 | 66.67% |
| 2.00 | +100 | 1/1 | 50% |
| 2.50 | +150 | 3/2 | 40% |
Implied probability is a price, not a forecast
At decimal odds of 2.50, the implied probability is 40%. That does not establish a 40% real chance of winning. Offered odds can include a bookmaker's margin; adding the probabilities of all outcomes can exceed 100%. This converter does not remove that margin or recommend selections.
Educational content for adults aged 18 and over. Past results do not guarantee future outcomes. These tools describe arithmetic, not betting strategies or investment advice.
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