What is Kelly Criterion?
A formula that calculates the optimal bet size based on your edge and the offered odds.
Definition
The Kelly Criterion mathematically derives the stake fraction that maximises long-term bankroll growth. Formula: f = (bp - q) / b, where b = decimal odds - 1, p = your win probability, q = 1-p. A 5% edge at decimal 2.00 = Kelly stake of 5% of bankroll. Full Kelly is theoretically optimal but real-world variance is brutal — most pros use Half-Kelly or Quarter-Kelly to soften drawdowns. Requires accurate probability estimates; over-confident estimates can wipe out your bankroll fast.
Example
Edge: 55% win probability at decimal 2.00 (50% implied). Kelly: (1.0 × 0.55 - 0.45) / 1.0 = 10% of bankroll. Half-Kelly = 5%.
Related terms
More from this category: Strategies & Edge
FAQ
What does "Kelly Criterion" mean in sports betting?
A formula that calculates the optimal bet size based on your edge and the offered odds.
How is "Kelly Criterion" used at the FIFA World Cup 2026?
Kelly Criterion applies to every World Cup 2026 match in the same way as any other regulated sports event. Fan Bet Odds tracks the relevant prices and lines across Bet365, Pinnacle, DraftKings, BetMGM and other licensed bookmakers — see the match prediction and odds pages for live application.
Where can I see "Kelly Criterion" in action on Fan Bet Odds?
Kelly Criterion appears throughout our match prediction pages (/odds/predictions/match/[slug]), market deep-dives (/odds/predictions/match/[slug]/[market]) and bookmaker reviews (/bet/bookmakers/[slug]). Use the related terms below to navigate the broader glossary.
World Cup 2026 - Daily Odds & Tips
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