Tools / Odds converter
Odds converter.
Convert betting odds between American, decimal and fractional formats, or turn odds into implied probability. No sign-up required.
HALFPOINT / ODDS CONVERTER
For example −150, 2.50, 5/2 or 0.40
How to use the odds converter
Enter a price such as −150, 2.50 or 5/2 and press Enter. Choose the odds format when prompted to see the equivalent prices and implied probability. You can also enter a probability as 0.40 or 40% to convert it back to odds.
Odds formats and implied probability
Every odds format states the same thing: what a winning bet pays. At +150 American, a $100 stake wins $150. That is 2.50 in decimal odds, 3/2 in fractional odds and an implied probability of 0.40 (40%).
American odds
A positive number is the profit on a $100 stake. A negative number is the stake needed to win $100, so −150 risks $150 to win $100.
Decimal odds
The total return per unit staked, stake included. Implied probability is 1 divided by the decimal odds, so 2.50 implies 0.40.
Fractional odds
The profit per unit staked. 5/2 wins 5 for every 2 staked, which is 3.50 in decimal odds.
Implied probability and vig
Converting odds to implied probability does not remove the sportsbook’s margin (vig). For example, two sides both priced at −110 each imply about 52.38%, totaling 104.76%. A market priced with a margin typically totals more than 100%; these are not necessarily the true chances of each outcome.
Odds conversion formulas
Let D be decimal odds, A the positive magnitude of American odds, and n/d fractional odds. Probability p is a number between 0 and 1; multiply it by 100 to get a percentage.
- Positive American odds to decimal: D = 1 + A / 100.
- Negative American odds to decimal: D = 1 + 100 / A.
- Fractional odds to decimal: D = 1 + n / d.
- Decimal odds to implied probability: p = 1 / D.
- Implied probability to decimal odds: D = 1 / p.
Betting odds conversion table
| American | Decimal | Fractional | Implied probability |
|---|---|---|---|
| −200 | 1.50 | 1/2 | 66.67% |
| −150 | 1.67 | 2/3 | 60% |
| −110 | 1.91 | 10/11 | 52.38% |
| +100 | 2.00 | 1/1 | 50% |
| +150 | 2.50 | 3/2 | 40% |
| +250 | 3.50 | 5/2 | 28.57% |
Odds converter questions
What does −110 mean in betting odds?
At −110, you stake $110 to win $100 in profit. It equals 10/11 fractional odds, about 1.91 decimal odds and 52.38% implied probability. A winning bet returns the stake plus the profit.
Are +100 and −100 the same odds?
Yes. Both mean even money: a $100 stake wins $100 in profit. They equal 2.00 decimal odds, 1/1 fractional odds and 50% implied probability.
Does converting odds change the payout?
No. American, decimal and fractional odds express the same price. Decimal odds include the returned stake; fractional and American odds describe profit. Displayed conversions may be rounded.
HalfPoint estimates live market-implied probabilities, updated in real time as markets move.
Consensus and Risk for the sharp side of the market.