Kelly fraction comparison
Compare Full / Half / Quarter / Tenth Kelly trajectories
Side-by-side projection of different Kelly fractions on the same bankroll, same edge, same horizon.
Why fractional Kelly matters
Full Kelly maximises expected geometric growth — but with brutal variance. Half Kelly captures ~75% of the growth with much less drawdown. Quarter Kelly is even safer but slower. This calculator plots all four trajectories on one chart so you can pick what fits your psychology. Combine with Drawdown calculator for risk probabilities and Kelly criterion for the math.
See also: Kelly criterion, Drawdown calculator, Bankroll growth simulator
How to use
- 1Enter your edge per bet (%).
- 2Enter starting bankroll.
- 3Enter horizon (number of bets).
- 4Compare projected final bankrolls and growth curves.
Example: 4% edge, 1000 bets
€1000 start, 4% edge, 1000 bets. Full Kelly: ≈€18k expected (but 20% chance of ruin). Half Kelly: ≈€11k expected (2% chance of ruin). Quarter Kelly: ≈€5k expected (<0.1% chance of ruin). Tenth Kelly: ≈€2k (essentially zero ruin risk). Pros use Half or Quarter — same direction, much better sleep.
When to use
- Choosing the right Kelly fraction for your risk tolerance
- Convincing yourself to stop using Full Kelly
- Educational visualization of compound math
Frequently asked questions
What is the Kelly fraction comparison calculator?
Full Kelly maximises expected geometric growth — but with brutal variance. Half Kelly captures ~75% of the growth with much less drawdown.
How does the Kelly fraction comparison calculator work in practice?
€1000 start, 4% edge, 1000 bets. Full Kelly: ≈€18k expected (but 20% chance of ruin). Half Kelly: ≈€11k expected (2% chance of ruin). Quarter Kelly: ≈€5k expected (<0.1% chance of ruin). Tenth Kelly: ≈€2k (essentially zero ruin risk). Pros use Half or Quarter — same direction, much better sleep.
When should I use the Kelly fraction comparison calculator?
Choosing the right Kelly fraction for your risk tolerance. Convincing yourself to stop using Full Kelly. Educational visualization of compound math.