Kelly criterion

Here is the wiki article. I like to spend 10 to 15 minutes to study the concept.

For an even money bet, the Kelly criterion computes the wager size percentage by multiplying the percent chance to win by two, then subtracting one. So, for a bet with a 70% chance to win (or .7 probability), doubling .7 equals 1.4, from which you subtract 1, leaving .4 as your optimal wager size—40% of available funds.