Brk or Bust · Kelly Bet Simulator
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Ternary rounds. Win + lose
2.40
decimal odds
$1,000<br>balance<br>49%
51%
0%
1/99<br>win
lose
push
round · easy
$00.00%<br>Confirm
History
End game<br>New game
Odds format
Decimal<br>Fractional<br>Ratio<br>American<br>Hong Kong<br>Indonesian<br>Malay
Challenge
Default<br>Easy<br>Medium<br>Hard
Betting input
Buttons<br>Slider
Coaching
Off<br>On
$0
final balance
median k
total won
avg k win
largest
streak
rounds won
total lost
avg k lost
largest
streak
rounds lost
Kelly scores
Event<br>Value<br>Perf
Outcomes
Chosen play<br>Optimal play
History
Continue<br>New game
The Kelly Criterion
Definition
Bet the fraction of bankroll that maximizes the long-run growth rate of your money — the size that compounds an edge fastest without ever risking ruin. It scales with the edge and shrinks with the odds; with no edge, it is zero.
f* =
pwin · odds − plose<br>odds · (pwin + plose)
Too little<br>You give up growth but keep the ride smooth: half the Kelly bet still captures three quarters of the growth at half the volatility.
Too much<br>Variance outruns the edge. Growth falls faster than it rose, and past roughly twice the Kelly bet a winning proposition compounds against you.
In practice<br>The real world is not a perfect-information game — the probabilities in the formula are your estimates, and the curve punishes overestimating an edge far more than underestimating one. Professionals bet a fixed fraction of full Kelly (half is common), and treat any bet they cannot size with confidence as a pass.
Scoring
The game grades every round with k, your bet divided by that round's Kelly bet: a pass scores 0, the optimal bet scores 1, a bet into a negative edge scores below 0, and anything past 2 is in the region where growth turns negative. The end-of-game charts bucket your k's — a tight cluster around 1, with passes on the trap rounds, is the mark of a disciplined bettor.
Calculator
Growth per round across every bet size, 0–100% of bankroll. The blue dot is the Kelly bet; past the red intercept the same edge loses money.
Decimal<br>Fractional<br>Ratio<br>American<br>Hong Kong<br>Indonesian<br>Malay
odds<br>win<br>lose<br>push
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