Kelly Criterion Calculator
Estimate full and half-Kelly stake fractions from win rate and payoff — use as a ceiling, not a mandate.
%
0.5 = half Kelly
Result
- Full Kelly
- 25%
- Fractional Kelly
- 12.5%
- Edge
- Positive
Educational calculator only — not financial advice. Markets move; verify with your broker and risk rules.
Frequently asked questions
Should I use full Kelly?
Full Kelly is aggressive and variance-heavy. Many traders use half or quarter Kelly, or ignore Kelly and stick to fixed fractional risk.
Log it where losses stay visible
Calculators size the trade. BuyNdSell is where the thesis, stop, and outcome stay on the record.