Parlay Calculator

Why Parlays Carry a Hidden House Edge

Sportsbooks calculate parlay payouts by multiplying the decimal odds of each leg. Since each individual line already has vig baked in, that vig compounds with every leg you add. A 3-leg parlay at -110 each has roughly 13% house edge compared to just 4.5% on a straight bet. The Monte Carlo simulator runs 10,000 trials to show you exactly how this edge plays out over time.