A parlay bet is a single bet that combines two or more selections, called legs, and pays only if every leg wins. The price is the prices of the legs multiplied together, so the payout grows with each leg you add, and so does the chance of losing.
A two-leg parlay at -110 on each side pays about +264, or $264 profit on $100, against $90.91 for either bet on its own. The catch is that both have to win: if each is a coin flip, the parlay comes in one time in four.
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How a parlay is priced
FanDuel’s house rules, approved by the Massachusetts Gaming Commission on March 27, 2025, say it in one line: “Parlay payoff – Odds will be calculated based on the prices of the individual selections.” In practice that means converting each price to decimal odds, multiplying them, and converting back.
Take three made-up prices: -110, -110 and +150.
| Step | Leg 1 | Leg 2 | Leg 3 |
|---|---|---|---|
| American price | -110 | -110 | +150 |
| Decimal price | 1.909 | 1.909 | 2.500 |
Multiply the decimals: 1.909 x 1.909 x 2.500 = 9.11. A $10 parlay returns $91.12, which is $81.12 of profit, or a price of about +811. A decimal price converts back to American by subtracting 1 and multiplying by 100 when it is 2.00 or higher.
What happens when a leg is void
A leg can be cancelled, for example when a game is abandoned or a player does not take part, and the book’s rule decides what the rest of the bet becomes. FanDuel’s same rules say the void leg drops out and “a treble including one void leg will become a double,” with the odds “re-calculated using the remaining legs.” If only one leg is left, it stands as a single bet.
So if the +150 leg in the example above were voided, the bet would become a two-leg parlay at -110 and -110, priced about +264. If a -110 leg were voided instead, the rest would pay about +377. A push is graded by each book’s own rules, so check the house rules at your book before you rely on it.
Why the house edge grows with every leg
A -110 price implies a 52.4% chance, and a bettor who wins exactly half their -110 bets loses about 4.5% of what they stake. Put two of those bets in a parlay and the loss rate roughly doubles, because the book’s margin is multiplied along with the prices.
Here is the arithmetic for legs that each win 50% of the time, at -110 apiece:
| Legs | Parlay price | Chance all win | Return per $100 staked |
|---|---|---|---|
| 1 | -110 | 50.0% | -$4.55 |
| 2 | +264 | 25.0% | -$8.88 |
| 3 | +596 | 12.5% | -$13.03 |
| 4 | +1228 | 6.3% | -$16.98 |
| 5 | +2436 | 3.1% | -$20.75 |
| 6 | +4741 | 1.6% | -$24.36 |
A parlay pays better than the legs do alone only when you have an edge on each leg. If you rate a side at 55% and the price implies 52.4%, a parlay multiplies that edge. If you have no edge, it multiplies the book’s.
Types of parlay
- Standard parlay: legs from different games, such as moneylines, spreads and totals.
- Same game parlay: legs from one game. FanDuel’s rules settle a void leg in a same game parlay the same way as any other parlay.
- Round robin: a set of smaller parlays built from one list of picks, so one loss does not sink all of them. Our round robin guide shows how the combinations add up.
- Teaser: a parlay in which every spread or total moves in your favor, paid from a fixed chart instead of the leg prices. See our teaser guide.
FanDuel’s rules apply the parlay rules to round robins too: “Round Robin wagers are subject to settlement in accordance with the parlay rules in this section,” so a void leg drops out of each small parlay it sits in.
Linked legs and what books refuse
Books do not want two legs that depend on each other in an ordinary parlay. FanDuel’s rules say parlays “are not accepted when there are related contingencies (i.e. where the outcome of one event is likely to affect the odds on the outcome of another event).” A same game parlay is the book’s own product for combining outcomes from one game, and it is priced by the book with that link in mind.
The same rules cap winnings at $1 million on any single bet, parlay or same game parlay included. That cap matters only on very long parlays, but it is worth knowing before you build one.
Mistakes to avoid
The first is adding legs for the payout. Each -110 leg you add cuts the chance of winning in half at 50% per leg, while the table above shows the book’s share climbing from 4.5% to more than 24% by the sixth leg.
The second is hedging late without doing the math. When one leg is left, you can bet the other side to lock in part of the payout; our hedging guide works through the numbers. Our odds explainer covers how to convert any price to a chance.
Where our calls are
A parlay is only as good as its legs, and our game predictions are where we name our side and the price.
This week’s NFL games are on our NFL predictions hub, with the NBA hub for basketball. For paid picks, our handicapper site reviews compare the services.