Odds and Log Odds

Converting Probability, $P$, to Odds, $O$:

Plug your probability into the following formula.
$O=\frac{P}{1-P}$
The result you get (imagine plugging in $P=0.75$ and getting $O=3$), is the odds of it happening. Therefore, the odds of that event would be 3 to 1 (three times more likely to occur).

Converting Odds to Log Odds:

Often we want to be able to express odds as a single number. To do that, simply take $ln(O)$. To convert it back, take $e^{ln(O)}$ to get $O$ (simple power arithmetic).