Implied Probability Calculator
Turn any odds into the true win percentage they imply.
This calculator converts odds into implied probability, the break-even win rate a price is asking you to believe. Enter American, decimal, or fractional odds, or enter a percentage to get the fair odds that match it.
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How the Implied Probability Calculator works
What is implied probability (implied odds)?
Implied probability is the win percentage baked into a betting price, and bettors often call it the implied odds. A -200 favorite implies a 66.7% chance to win; a +150 underdog implies 40%. It is the break-even rate: bet below it long term and you lose, above it and you profit. (In poker, implied odds means something else: future bets you expect to win.)
American odds implied probability formula (positive and negative)
Negative odds (favorites): implied probability = |odds| / (|odds| + 100). At -150 that is 150 / 250 = 60%. Positive odds (underdogs): implied probability = 100 / (odds + 100). At +150 that is 100 / 250 = 40%. The sign tells you which formula to use, and the same number on either side of 100 lands the same distance from 50%.
Implied probability from decimal and fractional odds
Decimal odds: implied probability = 1 / decimal, so 2.50 is 40% and 1.91 is about 52.4%. Fractional odds: for a / b, implied probability = b / (a + b), so 5/2 is 2 / 7 = 28.6% and 1/4 is 4 / 5 = 80%. The calculator handles every format instantly.
Implied vs. true probability
A book's implied probabilities include the vig, so they add up to more than 100%. The true probability is what is left once that margin is removed: a -110 / -110 market implies 52.4% per side, but the fair, true figure is 50% each. Your job is to estimate the true probability and bet when you think it is higher than the price implies. Pair this with the no-vig calculator to see the fair number.
From probability to fair odds
Flip it around: fair decimal odds = 1 / your probability. If you think a team wins 60% of the time, fair odds are 1.67 (about -150). Anything better than that price is value.
Odds to implied probability chart
Implied probability is the win rate a price is pricing in, and it doubles as your break-even rate: you need to win at least this often to profit at that number before vig. Favorites (minus) sit at the top, underdogs (plus) below. Enter any odds above for the exact figure.
| American odds | Implied probability | Decimal odds |
|---|---|---|
| -2000 | 95.2% | 1.05 |
| -1000 | 90.9% | 1.10 |
| -500 | 83.3% | 1.20 |
| -400 | 80.0% | 1.25 |
| -300 | 75.0% | 1.33 |
| -250 | 71.4% | 1.40 |
| -200 | 66.7% | 1.50 |
| -175 | 63.6% | 1.57 |
| -150 | 60.0% | 1.67 |
| -140 | 58.3% | 1.71 |
| -130 | 56.5% | 1.77 |
| -120 | 54.5% | 1.83 |
| -110standard | 52.4% | 1.91 |
| -105 | 51.2% | 1.95 |
| +100standard | 50.0% | 2.00 |
| +105 | 48.8% | 2.05 |
| +110standard | 47.6% | 2.10 |
| +120 | 45.5% | 2.20 |
| +130 | 43.5% | 2.30 |
| +140 | 41.7% | 2.40 |
| +150 | 40.0% | 2.50 |
| +175 | 36.4% | 2.75 |
| +200 | 33.3% | 3.00 |
| +250 | 28.6% | 3.50 |
| +300 | 25.0% | 4.00 |
| +400 | 20.0% | 5.00 |
| +500 | 16.7% | 6.00 |
| +750 | 11.8% | 8.50 |
| +1000 | 9.1% | 11.00 |
Two-way book prices add up to more than 100% because of the vig. Strip it out with the no-vig calculator to see the fair probability, or switch formats with the odds converter. Trading contracts instead of lines? The prediction market calculator charts every price from 0¢ to 100¢.
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Frequently asked questions
How do I calculate implied probability from odds?+
Use 1 / decimal odds, or 100 / (odds + 100) for positive American odds, or |odds| / (|odds| + 100) for negative American odds. The calculator does all three formats for you.
What is the implied probability formula for positive and negative American odds?+
For negative odds, divide the odds (without the minus sign) by the odds plus 100: -200 is 200 / 300 = 66.7%. For positive odds, divide 100 by the odds plus 100: +200 is 100 / 300 = 33.3%.
What is the implied probability of -110?+
-110 American odds imply about a 52.4% win probability, the standard break-even rate on a typical point spread.
How do I find the true probability of a bet?+
Remove the vig. Convert both sides of the market to implied probability, add them, and divide each side by the total so they sum to 100%. That fair figure is the market's true probability; the no-vig calculator does it in one step.
What does implied probability tell me?+
It is the break-even win rate. If your own estimate of a team's chances is higher than the implied probability, the bet has positive expected value.
How do I turn a percentage into odds?+
Fair decimal odds equal 1 divided by the probability. Enter a percentage in the calculator and it returns the matching fair American and decimal odds.