Three ways to describe a trade
Enter a starting and target price, American or decimal odds (single bets or parlays), or raw payoff multiples for any set of outcomes.
See KellyCalc on iPhone.
From your first scenario to a clearer view of the risk.
Describe the outcomes. Get a size.
List what could happen, give each outcome a probability and a return, and KellyCalc finds the allocation that maximizes long-term growth. If there's no edge worth taking, it tells you.
Full, Half, and Quarter Kelly
See the growth-optimal allocation as a percentage and in dollars, with clear warnings when a position has negative expected value.
Stress-test your conviction
Sensitivity analysis shows how your size shifts if any probability is off by 10 percentage points.
See what could happen
Monte Carlo simulation plays out sequences of up to 100 trades so you can see the range of bankroll paths your size implies.
Save your ideas
Store calculations as named ideas on your device and come back to them later.
No account
Open the app and start sizing. Your bankroll, scenarios, and saved ideas stay on your device.
Free to start. One purchase for unlimited.
Free
5 calculations every week, with every input mode and analysis.
Unlimited
Unlimited calculations with a single in-app purchase. No subscription.
Get KellyCalc.
For iPhone and iPad. No account needed.
Coming soon