{"uid":"cap__IrJK18XdLcPOoX_RrZd5","slug":"saylor-innovations-kelly-criterion-calculator-ccab1cb7","name":"Saylor Innovations Kelly Criterion Calculator","description":"Kelly criterion bet sizing from win probability and odds - full, half and quarter Kelly, expected log growth, break-even win rate and a verdict","url":"https://saylorinnovations.com/api/finance/kelly?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["win_prob","odds"],"properties":{"odds":{"type":"string","description":"Net payout per 1 staked (1 = even money)"},"win_prob":{"type":"string","description":"Probability of winning, 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Kelly criterion bet sizing (full, half, quarter Kelly) from win probability and odds, plus expected log growth, edge, break-even win rate, and a plain-language verdict","exampleAgentPrompt":"I think this bet has a 55% chance of winning and pays out 1.8 to 1 — can you run the Kelly criterion and tell me what fraction of my bankroll to stake, plus the half and quarter Kelly sizes and whether the bet has positive expected value?","exampleUseCases":[{"title":"Sports bet sizing decision","prompt":"I'm looking at a football bet where I estimate a 60% chance of winning and the bookmaker is offering 1.5 to 1 net odds — what does Kelly criterion say I should stake, and what are the half and quarter Kelly sizes?"},{"title":"Poker hand EV and sizing","prompt":"In this poker spot I figure I'm winning 72% of the time and the pot odds work out to 0.9 to 1 net — calculate the full Kelly fraction, the expected log growth, and tell me if it's worth playing."},{"title":"Trading strategy position sizing","prompt":"My backtested trading strategy wins 48% of the time with an average net payout of 2.2 per unit risked — use Kelly to figure out what fraction of capital to deploy and give me the break-even win rate so I know my margin of safety."}],"resultDescription":"A JSON object containing the win probability and net odds echoed back, full/half/quarter Kelly percentages, the full Kelly fraction, edge per unit staked, break-even win probability, expected log growth for full and half Kelly, a note providing context, and a plain-language verdict summarising whether the bet is worth taking and at what sizing.","failureModes":["Missing required query parameters win_prob or odds returns an error","win_prob outside 0-1 range may produce invalid or negative Kelly fractions","Odds of 0 or negative values may cause division errors","win_prob of exactly 0 or 1 may produce null expected log growth fields","Network or payment failure returns a 402 or 5xx error"],"whenToPreferThis":"Choose this endpoint when you need a complete Kelly criterion analysis in one call — including fractional Kelly variants, expected log growth, edge calculation, break-even win rate, and a verdict — rather than implementing the formula yourself or using a generic math tool. It is ideal for betting, trading position sizing, and any bankroll management scenario where you have a probability estimate and net odds.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-18T12:56:28.414Z","isFirstParty":false,"canonicalSlug":"saylor-innovations-kelly-criterion-calculator-ccab1cb7"}