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Edge Tool

Kelly tells you the ceiling, not the answer.

The Kelly criterion sizes a bet from win rate and payoff ratio alone. It is also famously aggressive when the inputs are even slightly wrong, which every trading edge estimate is.

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Kelly fraction (f*)

Kelly fraction (f*)
+14.4%

Positive Kelly fraction. Most traders should risk a fraction of this, not the full amount.

f* = (b*p - q) / b, where p = winRate/100, q = 1-p, b = payoffRatio
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Visual model

The tool should change the next decision, not just return a number.

Each tool gives a usable answer on the spot. No account needed.

At a glance
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Kelly Criterion Calculator
What you get

Kelly fraction (f*)

How to read it

Use the output as a review prompt, not a signal.

  • Formula: f* = (b·p − q) / b — the fraction of capital to risk per trade that maximizes long-run geometric growth.
  • Full Kelly is aggressive and assumes the inputs are exact. Most traders use a fraction of f*: 1/4 Kelly (25% of f*) or 1/2 Kelly (50% of f*) trade off some growth for much less drawdown.
  • Negative f* means there is no edge at this payoff ratio — the correct size is zero, not a smaller positive number.

Risk disclosure

This tool is educational. It does not place trades, recommend trades, or know your personal financial situation. Trading stocks, options, futures and crypto involves substantial risk of loss and is not suitable for everyone. You can lose more than you invest in leveraged products. Only trade money you can afford to lose. Past performance does not guarantee future results.

Methodology

Reviewed as educational research, not trade advice.

Futures-first risk math before product claims.
Every page answers your question before it asks anything of you.
Tools are educational and never produce trade recommendations.
Formulas are shown on the page. Results are educational, never trade recommendations.
Trust file
Author
Sage
Reviewed by
Sage
Updated
2026-05-28
Scope
Education only. Not trade advice.
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Where to go next

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Every calculator and guide here is free, no account needed. If you want to learn the craft, that is the Academy. If you want our trades as we take them, with alerts, that is Pro. New paid memberships are paused right now, so paid plans go through the waitlist.

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