All Calculators
Bankroll Management

Kelly Criterion

Calculate the mathematically optimal bet size to maximize long-term bankroll growth while managing risk.

Parameters

Kelly Formula
f* = edge / odds = 1.5% / 1
= 1.50% of bankroll
Full Kelly
$150
1.50%
Risk: High
Maximum growth rate but extreme volatility
Half Kelly
$75
0.75%
Risk: Medium
75% of max growth, much smoother ride
Quarter Kelly
$38
0.38%
Risk: Low
Conservative approach, minimal drawdowns

Growth Projection

Bets PlayedFull KellyHalf Kelly
100$2,308$4,804
500$7$256
1,000$0$7
5,000$0$0
Expected growth rate: -1.4664% per bet · Assumes independent identical bets

Key Insights

  • 1.Never bet more than Full Kelly — overbetting reduces long-term growth and dramatically increases risk of ruin.
  • 2.Half Kelly is recommended — you get 75% of the growth rate with far less volatility. Most professional bettors use this.
  • 3.Edge estimation matters — if you overestimate your edge, Kelly will tell you to bet too much. Be conservative with your edge estimate.
  • 4.Recalculate as bankroll changes — Kelly is a fraction of your current bankroll, so your bet size should adjust as you win or lose.