kelly criterion calculator
mathematically optimal stake sizing based on your edge
inputs
decimal: 1.91x
55%
bookmaker implied: 52.4%
25%
25% = conservative, 50% = moderate, 100% = aggressive
recommended stake
25% kelly
$137.50
1.38% of bankroll
expected value
+$6.88
+5.0% roi
full kelly
$550.00
5.50% bankroll
risk level
low
conservative sizing. low risk of significant loss.
recommendations
- • use 25% kelly for most bets (reduces variance)
- • use 50% kelly for high-confidence plays
- • never use 100% kelly (too aggressive for most)
- • track your clv (closing line value) over time
what is the kelly criterion?
the kelly criterion is a mathematical formula that determines the optimal stake size for a bet with a positive expected value. it maximizes long-term bankroll growth while minimizing the risk of ruin.
formula: kelly % = (bp - q) / b
- b = decimal odds - 1
- p = your estimated win probability
- q = 1 - p (loss probability)
most professional bettors use fractional kelly (typically 25-50%) to reduce variance and protect against overestimating their edge.