# Implied probability

**Implied probability **is the conversion of betting odds into a percentage. It shows the expected probability of an outcome and is used by sports bettors to understand if the odds being offered by a bookmaker are good value or not.

Implied probability is important because it takes into account the bookmaker's margin.

## How to calculate implied probability

Calculating implied probability is really simple but is slightly different depending on your preferred odds format.

### Converting decimal odds to implied probability

In order to calculate implied probability using decimal odds, simply divide 1 by the decimal odds and multiple it by 100.

(1 / decimal odds) * 100 = implied probability

For example, if the odds for Manchester United to beat Chelsea at home were 1.50, the implied probability of the home win would be 66.7%.

(1 / 1.5) * 100 = 66.66%

### Converting fractional odds to implied probability

To calculate implied probability using fractional odds, divide the denominator by the sum of the denominator + numerator, and then multiply by 100.

denominator / (denominator + numerator) * 100 = implied probability

For example, if the odds for Manchester United to beat Chelsea at home were 1/2, the implied probability of the home win would be 66.7%.

(1 / (1+2)) * 100 = 66.66%

### Converting American odds to implied probability

If you use American odds then you will need to calculate negative and positive odds using slightly different formulas.

#### Negative odds

To calculate implied probability for negative American odds, divide the odds by the sum of the odds + 100 and then multiple by 100.

Negative American odds / (Negative American odds + 100) * 100 = implied probability

For example, if the odds for Manchester United to beat Chelsea at home were -200, the implied probability of the home win would be 66.7%.

200 / (200 + 100) * 100 = 66.66%

#### Positive odds

To calculate implied probability for positive American odds, divide 100 by the sum of the odds + 100 and multiply by 100.

100 / (positive American odds + 100) * 100 = implied probability

For example, if the odds for Chelsea to beat Manchester United away from home were 200, the implied probability of the away win would be 33.3%.

100 / (200 + 100) * 100 = 33.33%

## How to use implied probability to improve your betting

Understanding implied probability is absolutely critical to becoming a long-term profitable sports bettor. Only by understanding the implied probability of betting odds are you able to understand if a bet represents value or not.

Simply put, if you're serious about making money from betting on sports then you should only ever place a bet if the expected probability of an outcome is greater than the implied probability of the betting odds.