How do parlays work? How the payout is calculated, why the house edge multiplies with every leg, and what pushes and same-game parlays change
Parlays are the bet type sportsbooks promote hardest, with boosts, insurance offers and same-game builders, and the reason is arithmetic rather than marketing. This guide works through the payout formula, one example from stake to expected value, the official hold data that shows what parlays return to operators, and the house rules that decide what happens when a leg does not finish cleanly.
How a parlay payout is calculated
Convert every leg to decimal odds, multiply, and multiply the result by the stake. Decimal odds include the stake: -110 is 1 + 100/110 = 1.9091; +130 is 2.30; -150 is 1.6667. A parlay of those three returns 1.6667 x 2.30 x 1.9091 = 7.318 times the stake, or +632 in American odds. If any leg loses, the parlay loses. A parlay can have two legs or many; DraftKings' house rules define it simply as a bet with "two or more legs."
The same multiplication applies to probabilities. A parlay wins only if every leg wins, so if the legs are independent the chance of winning is the product of the individual chances. Three legs that each win half the time land together one time in eight, 12.5 percent. Our parlay calculator does both multiplications for any combination of prices.
Worked example: three legs at -110
Take a $10 parlay of three point-spread bets, each priced at -110 on both sides, and assume each is a genuine 50-50 proposition.
| Step | Calculation | Result |
|---|---|---|
| Decimal odds per leg | 1 + 100/110 | 1.9091 |
| Parlay odds | 1.9091 x 1.9091 x 1.9091 | 6.958 (+596) |
| Return on a $10 win | $10 x 6.958 | $69.58 |
| Chance all three win | 0.5 x 0.5 x 0.5 | 12.5% |
| Fair odds at 12.5% | 1 / 0.125 | 8.000 (+700), a $80 return |
| Expected value | 0.125 x $69.58 - $10 | -$1.30, or -13.03% of stake |
For comparison, the same $10 on one -110 spread bet has an expected value of 0.5 x $19.09 - $10 = -$0.45, or -4.55 percent. Three separate $10 bets lose $1.36 on average on $30 staked. The parlay loses about the same amount in dollars on one third of the money, so the loss rate per dollar wagered is close to three times higher. That is the sense in which the edge multiplies.
Why the house edge grows with every leg
On a single -110 bet on a 50-50 event the bettor gets back 95.45 percent of the stake on average. Chain legs together and the return is 0.9545 raised to the number of legs. The edge is therefore 1 - 0.9545n:
| Legs at -110 | Parlay pays | Fair price | Chance to win | House edge |
|---|---|---|---|---|
| 1 | +91 | +100 | 50% | 4.55% |
| 2 | +264 | +300 | 25% | 8.88% |
| 3 | +596 | +700 | 12.5% | 13.03% |
| 4 | +1228 | +1500 | 6.25% | 16.98% |
| 5 | +2436 | +3100 | 3.13% | 20.75% |
| 6 | +4741 | +6300 | 1.56% | 24.36% |
| 8 | +17545 | +25500 | 0.39% | 31.08% |
| 10 | +64208 | +102300 | 0.10% | 37.20% |
Two things in that table are easy to miss. The gap between the parlay price and the fair price widens in absolute terms as well as in percentage: at ten legs the sportsbook pays +64,208 on a bet that is fairly worth +102,300. And the edge assumes each leg is priced at a standard -110. Legs with larger margins, such as player props or futures, push the figures higher; boosted legs or odds better than fair push them lower. The vig explainer shows how to measure the margin on any individual price.
What the state data shows
Most states do not publish parlay results separately, but Nevada does for one product. The Nevada Gaming Control Board's monthly revenue report lists "parlay cards", the paper sheets of fixed-odds parlays sold at sportsbook counters, as their own line. In the twelve months to July 2026 they produced $7.35 million of win at a 30.07 percent win rate. Football produced 7.29 percent, basketball 6.78 percent and all sports wagering together 7.69 percent over the same period. Parlay cards are a small, old-fashioned product with fixed payout tables, so the figure is an upper reference point rather than a measure of app parlays, but the ratio, roughly four times the overall hold, is in line with the arithmetic above.
The operators say the same thing in their own terms. When Flutter cut its 2024 US revenue guidance in January 2025, SBC Americas reported that winning parlays had cost FanDuel $438 million of gross gaming revenue, that about 70 percent of FanDuel's NFL and NBA wagering was parlays, and that FanDuel was targeting a 16 percent hold by 2030 from about 12 percent, citing "a higher structural margin element to the parlay products." Parlays also produce the most volatile results for operators: when favourites win across a weekend, parlay liabilities land together.
Pushes, voids and same-game parlays
A leg that ties the line or is cancelled does not usually void the bet. DraftKings' house rules, filed with the Massachusetts Gaming Commission, are typical: a parlay "shall not be voided solely due to a leg of that Parlay being voided or settled as Push"; the leg is removed and the parlay is repriced on the remaining legs, and the stake stays on the bet. Only if every leg is voided or pushed is the whole parlay voided. In the worked example, a push on one leg would turn the $10 three-leg bet into a two-leg bet at 3.645, returning $36.45 if both remaining legs win. A game that does not start within two calendar days of its scheduled time is voided under the same rules, and the leg drops out the same way.
Same-game parlays are treated differently because their legs are linked. A quarterback's passing yards and his team's points tend to rise together, so multiplying the two prices would overstate the payout. Standard parlays that combine correlated selections can be voided under DraftKings' rules; same-game parlays are exempt because the sportsbook prices the correlation itself and offers a combined price, which is usually below the straight product of the individual legs. The bettor sees one number and cannot easily separate the correlation adjustment from the margin.
Parlays on a prediction exchange
Kalshi sells the same structure as "combos". Instead of multiplying posted odds, the exchange runs a request for quote: the user picks the legs, market makers submit prices for the whole combination in a short window, and the user accepts or cancels the best one. Sportico reported that combos launched on September 30, 2025 and drew about $138 million of volume in their first six weeks. The margin sits inside the quoted price. A way to check it is to multiply the individual contract prices: three legs trading at 50 cents imply a fair combined price of 12.5 cents, so a combo quoted at 14 cents costs about 12 percent more than the legs suggest before any fee. Kalshi's general taker fee formula, 0.07 x contracts x price x (1 - price) rounded up to the cent, is set out in its fee schedule. The state tracker shows where these contracts are available.
What this guide does not cover
This guide does not cover teasers, round robins or progressive parlays, each of which has its own payout table, and it does not rank operators' parlay prices. The edge figures assume independent legs priced at -110 on true 50-50 events; real prices and real probabilities vary. The Nevada figure covers parlay cards only. Rule wording is quoted from one operator's filed house rules as of October 2026 and other operators' rules differ in detail. The Kalshi combo volume is as of November 2025, the most recent public figure we found.
Frequently asked questions
How is a parlay payout calculated?
Convert each leg to decimal odds and multiply them. Three legs at -110 (1.9091 each) give 1.9091 x 1.9091 x 1.9091 = 6.958, so a $10 parlay returns $69.58, a profit of $59.58, which is +596 in American odds. Every leg must win; one loss loses the whole bet.
Why do parlays lose more money than single bets?
Each leg carries the sportsbook's margin, and the margins multiply. A single -110 bet on a true 50-50 outcome has an expected loss of 4.55 percent of the stake. Three such legs in one parlay have an expected loss of 13.03 percent, and ten legs 37.2 percent.
What happens to a parlay if one leg pushes?
Under typical US house rules the pushed leg is removed and the parlay is repriced on the remaining legs; the stake is not refunded. DraftKings' rules filed with the Massachusetts Gaming Commission say this, and void the whole parlay only if every leg is voided or pushed.
Are same-game parlays different?
Yes. All legs come from one game, so the outcomes are often correlated. Sportsbooks price that correlation themselves rather than simply multiplying the leg odds, and the result is usually a payout below the straight product of the individual prices.
Can you build parlays on Kalshi?
Kalshi offers combos, its version of a parlay, priced through a request-for-quote system in which market makers bid on the whole combination. The margin is inside the quoted price rather than in a posted vig, so the comparison point is the product of the individual leg prices.
Related
- Parlay calculator: payout and implied probability for any combination
- Odds converter: American, decimal, fractional and implied probability
- What is the vig? How sportsbook margin works
- Implied probability explained: odds to percent, vig out
- Is Kalshi legal in your state? The 50-state tracker
Sources
- Nevada Gaming Control Board, Monthly revenue report, July 2026 (PDF), statewide sports pool lines, for the parlay card, football, basketball and total win and win percentages over twelve months.
- Massachusetts Gaming Commission, DraftKings house rules, 18 August 2025 (PDF), sections I(N), II(C)(ix), II(G)(ii)(5) and III, for parlay, push, void, postponement, correlation and same-game parlay rules.
- SBC Americas, Too many winning parlays lead to Flutter revenue downgrade, 8 January 2025, for the $438 million impact, the 70 percent parlay share, the hold figures and the structural margin quotation.
- Sportico, How Kalshi's parlay combos work, November 2025, for the request-for-quote process, launch date and volume.
- Kalshi, Fee schedule (PDF), for the taker fee formula, as of October 2026.
18+ only. This guide explains how bets and contracts are priced. It is not legal, tax, financial or betting advice, and it is not a recommendation to wager. If gambling stops being fun, help is available at 1-800-GAMBLER.