Parlay Calculator — payout, odds and true expected value
Add each leg to get combined parlay odds and payout. Add a devigged fair win probability per leg and you also get the parlay's real expected value instead of just the payout.
How parlay odds are calculated
Convert every leg to decimal odds, multiply them together, then convert back to American. Payout on a stake is stake × combined decimal odds.
Why vig compounds in parlays
Each leg carries the sportsbook's margin, and parlays multiply those margins together. A four-leg parlay of −110 legs can hold 15%+ against you. The only way a parlay is +EV is if every leg is individually +EV against a devigged fair price.
Correlation matters
This calculator assumes independent legs. Correlated legs — a QB passing yards over with his own receiver's receiving yards over — win together more often than the multiplication suggests, which is exactly why books limit them.