Existing Bet Calculator

Existing Bet Calculator Info

If you already have an existing bet on an event, the existing bet calculator will show you how much to wager on the same side or the opposite side while maximizing the expected growth of your bankroll.

Betting on the same side frequently comes into play when you are limited and want to know if further bets on the same side, perhaps at a reduced edge, are indicated.

Betting on the opposite side indicates when hedging out some of your risk will increase your expected bankroll growth. If you see an arbitrage opportunity, but are limited on the +EV side, bet as much as you can on that side and then immediately hedge using the opposite side calculation (Dan Abrams refers to this as an “autohedge”).

If your new bet is on a correlated event rather than the same game (such as hedging a futures position with a playoff game), use the Correlated Bet Calculator instead.

Odds: The odds of the new bet.
Probability: The probability the new bet wins.
True Odds: The fair / no-vig odds of the new bet.
Payout: The payout of the existing bet as a percentage of your bankroll.
Odds Format: Specifies the format used in odds fields.

Math

Same Side Kelly

f = p - (1 + w) \frac{q}{b}

Opposite Side Kelly

f = p (1 + w) - \frac{q}{b} = p - \frac{q}{b} + p w

f: The fraction of your bankroll to bet.
p: The probability the new bet wins.
w: The fraction of your bankroll represented by your existing bet.
q: The probability the new bet loses.
b: The net fractional odds of the new bet.

Book Links

As an Amazon Associate I earn from qualifying purchases.