Kelly Criterion Calculator

Estimate a capped full or fractional Kelly allocation. Results are deterministic educational calculations—not financial, tax, legal or investment advice.

Calculate instantly

Result

Prepares a Chat draft with these inputs and this result. Nothing is shared with QELLY until you choose Send.

Worked example

The calculator opens with this registered example. Replace one assumption at a time to see how the deterministic result changes.

Example inputs

{
  "winProbability": 55,
  "averageWin": 1.8,
  "averageLoss": 1,
  "fraction": 0.5,
  "maximumRiskPercent": 25
}

Example output

{
  "payoffRatio": 1.8,
  "fullKelly": 0.3,
  "fractionalKelly": 0.15,
  "maximumRiskCap": 0.25,
  "sensitiveEstimateWarning": true
}

Input glossary

Required inputs for this method: Win Probability, Average Win, Average Loss. Validation boundaries below come from the registered calculator schema.

Win Probability

Enter win probability for this calculation.

Required · Unit: % · Minimum: 0 · Maximum: 100

Average Win

Enter average win for this calculation.

Required

Average Loss

Enter average loss for this calculation.

Required

Fraction

Enter fraction for this calculation.

Optional

Maximum Risk Percent

Enter maximum risk percent for this calculation.

Optional · Unit: % · Minimum: 0 · Maximum: 100

Assumptions and limits

Method: Kelly Criterion · version 1.0.0 · formula ID kelly-criterion.
The calculation uses only the values entered on this page; it does not silently fetch live market data.
Fees, taxes, liquidity, slippage and other costs are included only when the registered inputs explicitly model them.
Display locale and rounding can change presentation, not the underlying deterministic receipt.

Edge cases

Inputs outside registered validation rules return an error rather than a fabricated result.
Array, matrix or cash-flow fields must be valid JSON in the structure described by their input label.
Extreme assumptions can be mathematically valid but economically unrealistic; use them as sensitivity tests rather than forecasts.

Frequently asked questions

Does this calculator require an account?

No. It works publicly without login. Calculations run locally. Explain result prepares a local Chat draft; your inputs and result are shared with QELLY only if you choose Send.

Is the result a recommendation?

No. It is a deterministic formula receipt whose usefulness depends on the assumptions you enter.

Why can market outcomes differ?

Fees, taxes, liquidity, volatility, timing and future returns may differ from the model assumptions.

Can I share my inputs?

Yes. Share creates an optional URL fragment containing only the inputs you choose to share. The fragment is not sent to QELLY by the calculator page.