Expected value · Kelly Criterion sizing · Promo optimizer
📋 How to use:Open your sportsbook app and build your parlay bet slip→Copy the American odds for each leg (e.g. -110, +150)→Paste them in below, add any active promo, and get your EV instantly
💰 My Bankroll
Your bankroll is used to calculate how much to bet via the Kelly Criterion. It's saved automatically in your browser.
🎁 Active Promo
Have an active promo from your sportsbook? Toggle it on and select the type below.
Profit Boost
Free Bet
Insurance
25%
e.g. A +25% boost on a parlay paying $400 profit raises it to $500 profit.
Free bets are worth ~60–75% of face value — you only collect profit, not the stake, when they win.
More legs = higher insurance value, since there are more ways exactly one can lose.
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🏈 Parlay Legs
📊 Analysis
Negative EV ← losing betwinning bet → Positive EV
🎁 Promo Impact
📐 Kelly Criterion — Bet Sizing
Half Kelly is the standard recommendation — it preserves most of the edge while significantly reducing variance.
🔍 Leg Breakdown
Implied probabilities include the sportsbook's margin (vig) and will sum to more than 100% across both sides of a market.