Chiefs -3.5 vs. Raiders at -110. You estimate the Chiefs cover 56% of the time. Bankroll: $5,000.
Step 1: Convert -110 to decimal: 1.909
Step 2: Kelly % = (1.909 × 0.56 - 1) / (1.909 - 1) = 0.069 / 0.909 = 7.6%
Step 3: Apply half Kelly = 3.8% of $5,000 = $190
Orioles +160 vs. Yankees. You give the Orioles a 45% chance to win. Bankroll: $5,000.
Step 1: Convert +160 to decimal: 2.60
Step 2: Kelly % = (2.60 × 0.45 - 1) / (2.60 - 1) = 0.17 / 1.60 = 10.6%
Step 3: Half Kelly = 5.3%, cap at 5% = $250
Lakers -110. You estimate them at 51% to cover. Bankroll: $5,000.
Kelly %: (1.909 × 0.51 - 1) / (1.909 - 1) = -0.026 or -2.6%
Result: Negative Kelly = no edge. Skip this bet.
Warriors/Suns Over 228.5 at -115. You estimate over hits 59% of the time. Bankroll: $6,000.
Step 1: Convert -115 to decimal: 1.870
Step 2: Kelly % = (1.870 × 0.59 - 1) / (1.870 - 1) = 0.103 / 0.870 = 11.8%
Step 3: Half Kelly = 5.9%, cap at 5% = $300
At BetLegend, we've tracked thousands of picks across NFL, NBA, NHL, and more. Here's what we've learned about using Kelly in practice: most bettors overestimate their edge. When we review our own historical data, the bets where we were most confident often had smaller edges than we thought. That's why we recommend starting with quarter Kelly (25%) until you have at least 200 graded bets proving your win rate is accurate.
Our approach? We use the calculator to identify bets where Kelly suggests at least 2% of bankroll. Anything under that usually means the edge is too thin to be reliable. It's a quick way to filter out marginal plays and focus on spots where you actually have meaningful value.