What are betting odds?

Betting odds are numbers set by bookmakers that indicate both the potential payout if a bet wins and the bookmaker's assessment of the probability of that outcome occurring. They are the price of a bet.

What is implied probability?

Implied probability is the percentage chance of an outcome occurring that is 'implied' by the betting odds offered by a bookmaker. It represents the bookmaker's belief about the likelihood of the event, including their built-in commission (vig).

How do I convert American odds to implied probability?

To convert American odds to implied probability: For positive odds (+X), the formula is Implied Probability (%) = 100 / (X + 100). For negative odds (-X), the formula is Implied Probability (%) = X / (X + 100) * 100, where X is the absolute value of the odds. For example, odds of +150 imply (100 / (150 + 100)) * 100 = 40%. Odds of -200 imply (200 / (200 + 100)) * 100 = 66.7% (approx.).

How does implied probability help me find value bets?

By calculating the implied probability from the bookmaker's odds and comparing it to your own estimated probability (based on analysis or data like Bet Better's), you can find value bets . If your estimated probability is higher than the implied probability, the bet offers a positive expected value (+EV).

Understanding Betting Odds and Implied Probability: The Price of a Bet

Q: How do I convert Decimal odds to implied probability?

To convert Decimal odds to implied probability, use the formula: Implied Probability (%) = (1 / Decimal Odds) * 100. For example, odds of 2.50 imply a probability of (1 / 2.50) * 100 = 40%.

Betting odds are the fundamental language of sports betting. They tell you two crucial things: how much you stand to win on a wager and, perhaps more importantly, the bookmaker's assessment of the likelihood of that event occurring. Learning to read odds across different formats and convert them into "implied probability" is a vital step towards becoming a more informed and successful bettor.

1. Different Formats of Betting Odds

Odds are displayed in several formats depending on your region or preference. The most common are Decimal, Fractional, and American (Moneyline) odds. While they look different, they all represent the same thing – the payout relative to your stake and the implied probability.

Learn more about common bet types on our How to Read Betting Lines page.

2. Converting Odds to Implied Probability

The implied probability is the bookmaker's quantitative prediction of how often an event will happen, based on the odds they offer. Converting odds to probability is essential for evaluating whether a bet offers value (i.e., a positive edge) compared to your own assessment. Remember that implied probability includes the bookmaker's vigorish (vig) or juice, which is their commission.

Decimal Odds Conversion

Formula: Implied Probability (%) = (1 / Decimal Odds) * 100

Example: Odds of 2.50

Implied Probability = (1 / 2.50) * 100 = 0.40 * 100 = 40%

Odds of 1.80 imply (1 / 1.80) * 100 = 55.6% (approx.)

Decimal odds are common in Europe, Canada, and Australia.

American (Moneyline) Odds Conversion

Formula (Positive Odds +X): Implied Probability (%) = 100 / (X + 100)

Example: Odds of +150

Implied Probability = 100 / (150 + 100) = 100 / 250 = 0.40 * 100 = 40%

Formula (Negative Odds -X): Implied Probability (%) = X / (X + X)

Example: Odds of -200

Implied Probability = 200 / (200 + 100) = 200 / 300 = 0.667 * 100 = 66.7% (approx.)

American odds are standard in the United States.

Fractional Odds Conversion

Formula (A/B): Implied Probability (%) = (B / (A + B)) * 100

Example: Odds of 5/2

Implied Probability = (2 / (5 + 2)) * 100 = (2 / 7) * 100 = 0.286 * 100 = 28.6% (approx.)

Example: Odds of Evens (1/1)

Implied Probability = (1 / (1 + 1)) * 100 = (1 / 2) * 100 = 50%

Fractional odds are traditionally used in the UK and Ireland.

Bet Better's tools include odds conversion features to help you quickly understand the implied probability regardless of format.

3. Using Implied Probability to Find Value

Understanding implied probability is key to identifying value bets. Value exists when your own estimated true probability for an outcome is higher than the implied probability offered by the bookmaker. This suggests the bookmaker has 'underpriced' the outcome.

Example: Finding Value

Bookmaker Odds (Decimal): 2.50 (Implied Probability: 40%)

Your Estimated True Probability (based on analysis/data): 50%

Since your 50% is higher than the bookmaker's 40%, this bet represents value (+EV).

How Bet Better Helps: Bet Better's core function is to provide you with accurate, data-driven estimated probabilities using our advanced analytics. We compare our estimated probability against the implied probability from bookmaker odds to highlight where the value lies, showing you our "Best Bets."

4. Odds vs. True Probability: The Importance of Vig

It's important to remember that the implied probabilities for all outcomes in a market (e.g., Home Win, Draw, Away Win) will typically add up to *more* than 100%. This excess percentage is the bookmaker's vigorish (vig) or juice – their guaranteed profit margin regardless of the outcome. A key part of sharp betting is finding odds that offer value *even after* accounting for the vig.

Conclusion: Odds Conversion is Your First Step

Learning to read betting odds and convert them into implied probabilities is a fundamental skill for any bettor moving beyond casual wagering. It allows you to understand the price you are getting and compare it against your own assessment of likelihood. By using tools like Bet Better to provide accurate probability estimates and identify discrepancies with implied odds, you can consistently find value and build a profitable long-term betting strategy.

Ready to go beyond reading odds and start finding value? Explore Bet Better Subscriptions and access the data and insights that reveal profitable opportunities.