Parlays explained: odds, payouts and the math

A parlay combines two or more bets into one ticket that pays only if every leg wins. Its odds are the decimal odds of every leg multiplied together: three legs at −110, which is 1.909 each, pay 6.96 times your stake, about +596. That same multiplication multiplies the sportsbook's margin, which is why a parlay of ordinary bets pays well below its true odds and gets worse with every leg you add. It is also why a parlay of genuinely good bets can be better than betting them one at a time.

How to work out parlay odds yourself

Convert every leg to decimal odds, multiply them, and convert the result back to American if you want it. Mixing favorites and underdogs changes nothing about the method. Most US books pay the straight product for legs from different games; for legs from the same game, the book sets its own price, covered below.

Why the house edge compounds

A single −110 bet on a true coin flip returns, on average, 0.5 × 1.909 = 0.9545 of your stake: you lose about 4.5% of what you bet over time. A parlay's average return is the product of each leg's average return, so two such legs return 0.9545 × 0.9545 and the loss grows with every leg. The payout looks larger and larger because it is, but the chance of collecting shrinks faster than the payout grows. Player props, with their wider margins, make the drop steeper.

What happens when a leg pushes or is void

At most US books, a leg that pushes or is voided is removed and the parlay is paid at the remaining legs' odds. A three-leg −110 parlay with one push becomes a two-leg parlay paying 1.909 × 1.909 = 3.64 instead of 6.96. Rules differ for same-game parlays and between books, so check the house rules before you rely on it.

Same-game parlays and correlation

Legs from one game are connected. If the Chiefs cover a big spread, the game was more likely high-scoring, so Chiefs −6.5 and Over 47.5 tend to win together. Multiplying the two prices would assume they are independent, which would underprice the pair, so books don't do it: a same-game parlay is priced by the book's own model of how the legs move together, and it usually pays less than the straight product. The book is both setting the correlation and adding its margin, and you can't see how much of each went into the price.

When do parlays make sense?

When every leg is a bet you would take on its own. If each leg is priced better than its true chance, the multiplication works for you instead of against you: two legs that are each +5% become a parlay that is +10.25%. The second case is promotions. Parlay boosts and profit boosts can add more than the margin takes away, and the bonus bets lesson shows how to value them. The third is honest entertainment: a small ticket for the fun of it, with the cost known in advance. The downside of the first two is variance; a +EV parlay still loses most of the time.

Teasers and round robins

A teaser is a parlay in which you move every spread or total in your favor by a set number of points in exchange for a lower payout. A round robin turns a list of picks into every smaller parlay they can make, such as all three two-leg parlays from three picks. Neither escapes the arithmetic above: each is a set of parlays, and each one's margin compounds the same way.

Building parlays on TrueEdge

The Parlay Builder searches the live board for positive-EV parlays at the book you choose: you set the target book, number of legs, maximum odds and leagues, and it returns combinations priced against fair odds. It takes at most one leg per game, so the combined price is a true product, and it does not build same-game parlays. It is part of the paid plans; see pricing. To price legs you already have, the Parlay tab in the free calculators multiplies up to 12 legs you type in; the combined probability it shows comes from your prices, so it is the book's number, margin included. The calculators walkthrough explains both.