Implied Probability Calculator
This calculator converts betting odds (American, Fractional, or Decimal) into the implied probability of that outcome occurring. Enter one set of odds to see the percentage probability.
Enter Betting Odds (Choose One Type)
Understanding Implied Probability
What is Implied Probability?
Implied probability is a way to convert betting odds into a percentage that reflects the likelihood of that event happening, as perceived by the bookmaker. It helps bettors understand the risk and potential reward associated with a particular bet and compare odds from different sources.
Formulas for Converting Odds to Implied Probability
The formula used depends on the format of the odds:
- American Odds:
- For positive odds (e.g., +150):
Probability = 100 / (Odds + 100) - For negative odds (e.g., -200):
Probability = |Odds| / (|Odds| + 100) - *Result is a decimal; multiply by 100 for percentage.
- For positive odds (e.g., +150):
- Fractional Odds (a/b):
Probability = b / (a + b)- *Result is a decimal; multiply by 100 for percentage.
- Decimal Odds:
Probability = 1 / Odds- *Result is a decimal; multiply by 100 for percentage.
Note: Implied probability includes the bookmaker's margin (vigorish or vig), so the implied probabilities for all possible outcomes in an event will typically add up to slightly *over* 100%.
Implied Probability Examples
See how different odds convert to implied probability:
Example 1: American Odds +200
1. Odds: +200 (American)
2. Formula: For positive American odds: `Probability = 100 / (Odds + 100)`
3. Calculation: Probability = 100 / (200 + 100) = 100 / 300 = 0.3333
4. Result: 33.33%
Conclusion: Odds of +200 imply a 33.33% chance of the outcome happening according to the bookmaker.
Example 2: American Odds -150
1. Odds: -150 (American)
2. Formula: For negative American odds: `Probability = |Odds| / (|Odds| + 100)`
3. Calculation: Probability = 150 / (150 + 100) = 150 / 250 = 0.60
4. Result: 60.00%
Conclusion: Odds of -150 imply a 60.00% chance of the outcome happening according to the bookmaker.
Example 3: Fractional Odds 5/1
1. Odds: 5/1 (Fractional)
2. Formula: `Probability = b / (a + b)`
3. Calculation: Probability = 1 / (5 + 1) = 1 / 6 ≈ 0.1667
4. Result: 16.67%
Conclusion: Odds of 5/1 imply a 16.67% chance.
Example 4: Fractional Odds 2/5
1. Odds: 2/5 (Fractional)
2. Formula: `Probability = b / (a + b)`
3. Calculation: Probability = 5 / (2 + 5) = 5 / 7 ≈ 0.7143
4. Result: 71.43%
Conclusion: Odds of 2/5 imply a 71.43% chance.
Example 5: Decimal Odds 3.50
1. Odds: 3.50 (Decimal)
2. Formula: `Probability = 1 / Odds`
3. Calculation: Probability = 1 / 3.50 ≈ 0.2857
4. Result: 28.57%
Conclusion: Decimal odds of 3.50 imply a 28.57% chance.
Example 6: Decimal Odds 1.25
1. Odds: 1.25 (Decimal)
2. Formula: `Probability = 1 / Odds`
3. Calculation: Probability = 1 / 1.25 = 0.80
4. Result: 80.00%
Conclusion: Decimal odds of 1.25 imply an 80.00% chance.
Example 7: American Odds +100 (Even Money)
1. Odds: +100 (American)
2. Formula: `Probability = 100 / (Odds + 100)`
3. Calculation: Probability = 100 / (100 + 100) = 100 / 200 = 0.50
4. Result: 50.00%
Conclusion: Odds of +100 imply a 50% chance (also known as even money).
Example 8: Fractional Odds 1/1 (Even Money)
1. Odds: 1/1 (Fractional)
2. Formula: `Probability = b / (a + b)`
3. Calculation: Probability = 1 / (1 + 1) = 1 / 2 = 0.50
4. Result: 50.00%
Conclusion: Odds of 1/1 imply a 50% chance (even money).
Example 9: Decimal Odds 2.00 (Even Money)
1. Odds: 2.00 (Decimal)
2. Formula: `Probability = 1 / Odds`
3. Calculation: Probability = 1 / 2.00 = 0.50
4. Result: 50.00%
Conclusion: Decimal odds of 2.00 imply a 50% chance (even money).
Example 10: American Odds +500
1. Odds: +500 (American)
2. Formula: `Probability = 100 / (Odds + 100)`
3. Calculation: Probability = 100 / (500 + 100) = 100 / 600 ≈ 0.1667
4. Result: 16.67%
Conclusion: Odds of +500 imply a 16.67% chance.
Frequently Asked Questions about Implied Probability
1. What is implied probability?
Implied probability is the conversion of betting odds into a percentage, representing the bookmaker's assessment of the likelihood of an event happening.
2. How is implied probability different from actual probability?
Implied probability includes the bookmaker's margin (vig or juice), which means the probabilities for all outcomes in an event will sum to over 100%. Actual probability is the true chance, which would sum to exactly 100% (excluding the vig).
3. Why would I calculate implied probability?
It helps you understand the perceived likelihood of an outcome, compare odds from different bookmakers, and potentially identify "value bets" if you believe the bookmaker's implied probability is lower than your own assessment of the actual probability.
4. How do I calculate implied probability for American odds?
For positive odds (+): 100 / (Odds + 100). For negative odds (-): |Odds| / (|Odds| + 100). Then multiply the result by 100 for a percentage.
5. How do I calculate implied probability for Fractional odds (a/b)?
The formula is b / (a + b). Multiply the result by 100 for a percentage.
6. How do I calculate implied probability for Decimal odds?
The formula is 1 / Odds. Multiply the result by 100 for a percentage.
7. Can implied probability be over 100%?
No, implied probability for a single outcome cannot exceed 100%. However, the sum of implied probabilities for all possible outcomes in a single betting market will be over 100% due to the bookmaker's margin.
8. What do odds of +100, 1/1, or 2.00 mean in terms of probability?
All three represent "even money" and imply a 50% probability. If you bet $100, you win $100 profit.
9. What are "value bets"?
A value bet is when you believe the actual probability of an outcome is higher than the implied probability offered by the bookmaker's odds.
10. What happens if I enter more than one type of odds?
The calculator is designed to use only one input. If you enter values in multiple fields, it should show an error and ask you to enter only one.
