Kelly Fraction Calculator for General Binary Bets

This calculator gives you the Kelly fraction for a general binary bet, given the probability of winning the bet (p), the return for winning the bet (r1 = α1 - 1), and the return for losing the bet (r2 = α2 - 1).

p: = probability of winning the bet.
r1: = return on your bet if you win ( > 0 ).
r2: = return on your bet if you lose ( < 0 ).

Note:

  • The case of r2 = -1 (or α2 = 0) is a coin toss bet, meaning when you lose, you lose your entire bet. Our Kelly Fraction Calculator for Coin Toss Bets treats this special case.
  • Getting a negative value for the Kelly fraction means don't bet, unless you can "sell short" the bet.