Implied Probability Calculator

Enter odds in any format to find the implied probability of that outcome.

American odds (e.g. -110, +250)

Decimal odds (e.g. 1.91)

Fractional numerator

Fractional denominator

Implied probability —

American odds —

Decimal odds —

Fractional odds —

Implied probability = 1 / decimal odds. Bookmaker margins mean the sum of all outcomes' implied probabilities exceeds 100%. The excess is the "vig" or "juice".

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Understanding Implied Probability

Implied probability is the probability of an outcome as reflected by the betting odds. It tells you what the market believes about the likelihood of each outcome.

To find value bets, compare implied probability to your own estimated probability. If you believe a team has a 60% chance of winning but the odds imply only 50%, that may be a value bet.

Implied probability converts betting odds to the percentage likelihood the sportsbook implies for an outcome. American odds: for positive odds (+150), implied prob = 100 / (odds + 100) = 100/250 = 40.0%. For negative odds (−150), implied prob = |odds| / (|odds| + 100) = 150/250 = 60.0%.

The overround (vig/juice): if you sum the implied probabilities of all outcomes in a market, they exceed 100%. A coin flip market at −110 both ways: both sides at 52.4% implied = 104.8% total. The 4.8% excess is the sportsbook's margin. You need your actual win rate to exceed the implied probability to have positive expected value.

Converting decimal odds: implied probability = 1 / decimal odds. Decimal odds of 1.909 (−110 American) → 1/1.909 = 52.4%. Decimal odds of 2.00 (±100 American, even money) → 1/2.00 = 50%.

Finding value bets: if you estimate a team has a 55% chance of winning but the implied probability from the odds is only 47%, the bet has positive expected value (EV). EV = (probability of winning × payout) − (probability of losing × stake). Consistent positive EV bets are necessary for long-term profitability, but predicting outcomes more accurately than the market is genuinely difficult.

For educational use. Problem gambling resources: NCPG Helpline 1-800-522-4700.