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Kelly Position Sizing & Fixed Fractional Risk Calculator
x402
Kelly Position Sizing & Fixed Fractional Risk Calculator is a paid API for AI agents from api.24klabs.ai, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).
Calculates optimal bet/trade size using full or fractional Kelly Criterion from win probability and payoff ratio, or fixed fractional sizing from stop distance and account risk percentage.
Price / call$0.003
Success—
StatusUnknown
How this service works
Optimal stake from win probability, payoff ratio and bankroll (full or fractional Kelly), plus fixed fractional risk sizing from stop distance and account risk %.
Output
Returns the recommended position size or stake amount — including the Kelly stake (in currency or fraction of bankroll) for full or fractional Kelly configurations, and/or the fixed fractional dollar risk and position size based on stop distance and account risk percentage. May also return intermediate values like the raw Kelly fraction before scaling.
Example use cases
Sports betting bankroll management
“I have a $5,000 betting bankroll and I think this bet has a 58% chance of winning at 2:1 odds — what's my optimal full Kelly stake, and what would a half-Kelly stake be?”
Stock trade position sizing
“I'm buying a stock with my $50,000 trading account and my stop loss is $3.50 away from my entry — how many dollars should I risk using fixed fractional sizing at 1.5% account risk?”
Options trade sizing with Kelly
“I have a 65% estimated win rate on this options trade with a 1.8 payoff ratio and a $30,000 account — compute my quarter-Kelly position size so I'm not over-leveraging.”
Technical details
Endpoint
POSThttps://api.24klabs.ai/api/v1/kelly-position-sizingWhen to prefer
Use this endpoint when you need a mathematically rigorous position sizing recommendation grounded in Kelly Criterion theory or fixed fractional risk management. Prefer it over manual calculation or generic advice when the user has quantified win probability and payoff ratio (for Kelly) or a defined stop distance and risk percentage (for fixed fractional). Best suited for traders, sports bettors, or algorithmic systems that need consistent, repeatable sizing logic embedded in an automated workflow.
Side effects
- Win probability outside 0–1 range returns a validation error
- Negative or zero payoff ratio returns an error
- Kelly fraction parameter outside valid range (e.g. > 1) may be rejected or clamped
- Missing required fields (e.g. bankroll without win probability) returns 400-level error
- Negative Kelly result (when edge is negative) may return zero or an explanatory message indicating the bet should not be placed
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| bankroll | number | |
| win_prob | number | |
| kelly_fraction | number | |
| win_loss_ratio | number |
Output
Schema · Response
{
"type": "json",
"example": {
"kelly_pct": 32.5,
"applied_kelly_pct": 16.25,
"recommended_stake": 1625
}
}Tags
x402
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