The formula to convert fractional odds to decimal is as follows: (numerator/denominator) + 1 = decimal odds. How do you convert fractional odds to American? For fractions greater than 1, the formula is as follows: (fractional value) * 100 = American odds.
To convert from odds to a probability, divide the odds by one plus the odds. So to convert odds of 1/9 to a probability, divide 1/9 by 10/9 to obtain the probability of 0.10.