[bookiebust]

Here is a second request on a similar theme. Can anyone tell me the mathematics of how to calculate fractional, US, or decimal odds from just an Implied Probability percentage alone? Again, I know there are converters available, but I would like to calculate this for myself. Thanks. --

[Juret]

1 / Decimal Odds = Implied Probability

[Blax0r]

Another approach would be to use the expected value equation (but it will boil down to Juret's answer):

EV = prob(win) * amount won - prob(loss) * bet amount

1. Set this to zero and plug in your implied probability of win (note: prob(loss) = 1 - prob(win)).
2. For demonstration purposes, I recommend setting bet amount to 100 if implied probability < 50, and setting amount won to 100 if implied probability > 50.
3. Solve for the unknown; if you are solving for bet amount, make sure to set your answer to a negative.
4. Throw an air fist pump, you just figured out the equivalent US odds.

[wrongturn]

US odds is pretty simple.
For p>50% (ie favorite), it is -100*p/(1-p); otherwise (dog) it is 100*(1-p)/p.