Decimal 2.50
Implied probability is 1 ÷ 2.50 = 40%. The equivalent formats are fractional 3/2 and moneyline +150.
Odds and Probability Converter
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Equivalent odds
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Odds conversion formulas
| Starting format | Implied probability | Decimal odds |
|---|---|---|
| Decimal D | p = 1 / D | D |
| Fractional a/b | p = b / (a + b) | D = 1 + a/b |
| Positive moneyline +A | p = 100 / (A + 100) | D = 1 + A/100 |
| Negative moneyline −A | p = A / (A + 100), using A as the positive magnitude | D = 1 + 100/A |
| Probability p | p | D = 1/p |
Decimal odds include the returned stake. Fractional and moneyline odds describe profit relative to stake. The percentage shown is the break-even probability encoded by one price before removing any bookmaker margin.
How to read betting odds
Decimal odds show total return per unit staked. At 2.50, a winning 10-unit stake returns 25 units in total: 15 units of profit plus the original 10-unit stake.
Fractional odds show potential profit relative to stake. Odds of 3/2 mean 3 units of profit for every 2 units staked. Adding the returned stake gives decimal odds of 1 + 3/2 = 2.50.
American moneyline odds use two directions. Positive odds show profit from a 100-unit stake, so +150 means 150 units of profit. Negative odds show the stake needed for 100 units of profit, so −200 means staking 200 units for 100 units of profit.
Implied probability is a break-even rate
At decimal odds D, the implied probability is 1/D. This is the win rate at which the expected gross return equals the amount staked, before costs. It is a price-derived threshold, not proof that an outcome has that true probability.
Important: Bookmaker prices may include margin (overround or vig), and payout rules can vary. This converter performs arithmetic only; it does not predict outcomes or provide betting or financial advice. Check the operator’s rules and comply with applicable age and gambling laws.
Worked odds examples
Fractional 4/5
Decimal odds are 1 + 4/5 = 1.80. Implied probability is 5 ÷ 9 = 55.5556%, and the equivalent moneyline is −125.
Moneyline −200
Decimal odds are 1 + 100/200 = 1.50. Implied probability is 200 ÷ 300 = 66.6667%, and fractional odds are 1/2.
Probability 25%
Decimal odds are 1 ÷ 0.25 = 4.00. Equivalent fractional odds are 3/1, and the moneyline is +300.
Frequently asked questions
How do I convert decimal odds to implied probability?
Divide 1 by the decimal odds, then multiply by 100. Decimal odds of 2.50 imply 40% because 1 ÷ 2.50 = 0.40.
How do I convert fractional odds to decimal odds?
Divide the numerator by the denominator and add 1. Fractional odds of 3/2 become 1 + 3/2 = 2.50.
How do positive and negative moneyline odds work?
A positive moneyline shows profit on a 100-unit stake. A negative moneyline shows the stake needed for 100 units of profit. For example, +150 converts to decimal 2.50, while −200 converts to decimal 1.50.
Are implied probability and true probability the same?
Not necessarily. Implied probability is the break-even percentage encoded by the displayed odds. Bookmaker margin and market assumptions mean it is not a prediction or guarantee of the true chance.
Why can implied probabilities add to more than 100%?
Prices for every possible outcome often include a bookmaker margin, also called overround or vig. Convert all mutually exclusive outcomes and add their percentages to measure the raw overround.
What is even money in each odds format?
Even money is decimal 2.00, fractional 1/1, moneyline +100, and an implied probability of 50%.
Does the converter store my odds or stake?
No. All conversion happens locally in your browser. The converter does not upload or store your entries.