Bankroll & Kelly criterion calculator
- Suggested stake (Kelly-capped)
- $0.00
- EV per $1 bet
- $0.960
- Expected rounds to half bankroll
- 17
Raw Kelly: -4.0%. Capped at 25% (quarter-Kelly) for variance sanity. Negative Kelly = the bet has negative expected value; suggested stake is $0.
How to use this
For any gambling game with known win probability and win multiplier (Coinflip 50% × 2x; Crash 48% × 2x; Plinko 16-row high outermost 0.0015% × 935.5x; etc.) enter the values and the calculator returns the EV-optimal stake size.
For most casino games (any house-edge game), Kelly will be negative — the calculator caps at $0. The correct “optimal stake” on a negative-EV game is $0; everything else is entertainment spend, not an investment.
Related
Frequently asked questions
- What is the Kelly criterion?
- Kelly is the bet-sizing formula that maximises long-run logarithmic bankroll growth. Formula: f* = (bp - q) / b, where b = payout-1, p = win probability, q = 1-p. The result is the fraction of bankroll to stake per bet.
- Why cap at quarter-Kelly?
- Full Kelly is mathematically optimal but extremely volatile — bankroll swings of 50%+ are routine. Quarter-Kelly (25% of the suggested fraction) reduces variance dramatically with only modest growth-rate penalty.
- What if the Kelly fraction is negative?
- Negative Kelly means the bet has negative EV — you should not bet. The calculator caps at $0 (no negative stakes).
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