KELLY CRITERION CALCULATOR
Kelly criterion calculator.
American odds. Your bankroll. Your own win estimate. See the calculated stake change in your browser, with no account required.
Explore plans & free accessYOUR ASSUMPTIONS
Run the numbers.
Example inputs, not a betting recommendation. Use your own probability estimate. No account or server request required.
CALCULATED STAKE
8.33% of bankroll
- Break-even win chance
- 40.00%
- Full Kelly allocation
- 16.67%
Rounded down to cents. A larger stake increases exposure to an incorrect probability estimate.
The formula behind the figure.
Convert American odds to decimal odds, d. Let p be your estimated win probability as a decimal. Full Kelly is (d × p − 1) / (d − 1), with negative results set to zero. Half and quarter Kelly multiply that allocation by 0.5 and 0.25. Stakes round down to cents.
The default inputs are a worked example, not a forecast. This tool does not estimate your edge, model correlated bets or protect you from losses. For records around your decisions, explore the bankroll workflow.
THE DETAILS
Before you decide.
What does the Kelly calculator calculate?
It calculates a stake allocation from your bankroll, American odds and estimated win probability. You can select full, half or quarter Kelly. When the estimate implies no positive edge, the stake is zero.
Where does the win probability come from?
You supply it. This calculator does not predict the outcome or verify your estimate. An overly optimistic probability can produce an overly large stake.
Does it work without an account?
Yes. Calculations run in your browser without sign-in or a server request. Inputs are not saved by the calculator. The site may have separate analytics configured.
Can I use it for correlated parlay legs?
The calculator accepts a single outcome probability. It does not model correlations between parlay legs. You would need an appropriate estimate for the combined outcome.
Is a Kelly stake safe or guaranteed?
No. The formula relies on your probability estimate and does not guarantee a return. Even a correctly calculated allocation can lose.
21+. Educational and entertainment use. Estimates depend on assumptions. You may lose money. StakeSmith does not accept or place wagers.