Probability Converter

Q: Which odds format is the best?

There is no "best" format, it depends on preference and location. Decimal Odds (common in Europe/Brazil) are easiest to understand. American Odds are standard in the US, and Fractional in the UK.

Q: What is Implied Probability?

It is the chance of an event occurring as estimated by the bookmaker. If the implied probability is lower than your actual probability estimate, you found a "Value Bet".

Q: How to read negative American odds?

Negative odds (e.g., -150) indicate how much you need to bet to win $100. Positive odds (e.g., +200) indicate how much you win if you bet $100.

Q: Why do bookmakers use different formats?

It is mainly a matter of regional tradition. The Decimal format is becoming the global standard due to its simplicity in calculating returns.

Convert between decimal, fractional, and American probability formats

Formula Explanation

Understanding different odds formats is essential for bettors using international bookmakers.

Conversion Formulas

Decimal to Fractional:
Subtract 1 from the decimal odd and convert to a fraction.
Ex: 2.50 - 1 = 1.5 = 3/2

Decimal to American:
If Odd >= 2.00: (Odd - 1) × 100
If Odd < 2.00: -100 / (Odd - 1)

Implied Probability:
Probability (%) = (1 / Decimal Odd) × 100

Example

Converting Decimal Odds (2.50)

Let's convert decimal odd 2.50 to other formats:

1. To Fractional

Subtract 1: 2.50 - 1 = 1.5

Convert to fraction: 1.5 = 15/10 = 3/2

2. To American

Since 2.50 >= 2.00, it is positive.

Calculation: (2.50 - 1) × 100 = 1.5 × 100 = +150

3. Implied Probability

Calculation: (1 / 2.50) × 100 = 0.40 × 100 = 40%

Frequently Asked Questions

Which odds format is the best?

What is Implied Probability?

How to read negative American odds?

Why do bookmakers use different formats?