Twenty dollars on three legs, priced at -110, +150 and -200, comes back as $143.18 if all three win. Get one wrong and it comes back as nothing. The parlay calculator above, a parlay payout calculator at heart, does that multiplication for any number of legs, which is the whole point of a parlay and also the whole problem with it.
Treat it as a parlay payout calculator first: enter the legs and the stake, and it shows the total return, the profit and the combined odds in American and decimal form. It also shows the number most parlay slips leave off, which is how much margin the ticket carries compared with the fair price.
How to use the parlay calculator
Add one row per leg and enter its odds in American, decimal or fractional form. Mixed formats are fine; the tool converts them all to decimal before multiplying. Then enter the stake.
The output gives four figures. Total payout is stake times combined decimal odds. Profit is payout minus stake. Combined odds are shown as decimal and as American. The implied chance, which doubles as the break-even rate, is the share of the time a ticket at that price has to win to break even, which is 1 divided by the combined decimal odds.
Legs can run from two to twelve. To see how a ticket pays after a push or a void, clear that leg’s odds: an empty row is skipped, and most sportsbooks settle a pushed or voided leg the same way, by dropping it and paying on the rest. The house rules of each book are what count, so check them for the market in question.
Parlay odds: the formula
A parlay is a chain of bets where the full return of each leg rides on the next one. That is why the decimal odds multiply.
| Step | Calculation |
|---|---|
| Decimal odds of each leg | +A → 1 + A/100; −A → 1 + 100/A |
| Combined decimal odds | leg 1 × leg 2 × … × leg n |
| Total payout | stake × combined decimal odds |
| Profit | payout − stake |
| American odds of the parlay | (combined − 1) × 100 when combined ≥ 2.00 |
Nothing in the formula cares which sports the legs come from. It does care whether the legs are independent of each other, and that is the catch with a same game parlay, covered further down.
Worked example: the payout on a three-leg ticket
Start with the ticket from the opening:
| Leg | American | Decimal |
|---|---|---|
| Leg 1 | -110 | 1.9091 |
| Leg 2 | +150 | 2.5000 |
| Leg 3 | -200 | 1.5000 |
| Combined | +616 | 7.1591 |
The combined decimal odds are 1.9091 × 2.50 × 1.50 = 7.1591. A $20.00 stake returns $20.00 × 7.1591 = $143.18, so the profit is $123.18. In American terms the parlay is (7.1591 − 1) × 100 = +616.
Now suppose the -200 leg is a spread that lands exactly on the number and pushes. The leg drops out, and the ticket is now a two-leg parlay at 1.9091 × 2.50 = 4.7727. The payout falls to $20.00 × 4.7727 = $95.45. Many bettors expect a pushed leg to kill the ticket; at most books it only shortens it.
A familiar price is a useful sanity check. Two legs at -110 multiply to 1.9091 × 1.9091 = 3.6446, which is the +264 that sportsbooks often post for a two-team parlay at standard prices.
A side-track: the round robin
A round robin splits one set of picks into every smaller parlay it contains. Take the same three legs and play them as a round robin by twos at $10.00 per ticket. That is three two-leg parlays and $30.00 in total stakes.
| Two-leg ticket | Combined decimal | Return on $10.00 |
|---|---|---|
| Leg 1 + Leg 2 | 4.7727 | $47.73 |
| Leg 1 + Leg 3 | 2.8636 | $28.64 |
| Leg 2 + Leg 3 | 3.7500 | $37.50 |
If all three legs win, the three tickets return $113.86, a profit of $83.86. If the -200 leg loses, only the first ticket survives, returning $47.73 for a profit of $17.73 on the $30.00. The round robin trades the top payout for a softer landing when one leg misses. Run each ticket through the parlay payout calculator separately; the arithmetic is the same as for a single parlay, repeated.
Why the odds get worse with every leg
Every leg carries its own margin, and the margins multiply along with the prices. The cleanest way to see it is a ticket of legs that are each a coin flip priced at -110.
| Legs at -110 | Combined decimal | American | Fair price | House edge |
|---|---|---|---|---|
| 1 | 1.9091 | -110 | +100 | 4.55% |
| 2 | 3.6446 | +264 | +300 | 8.88% |
| 3 | 6.9579 | +596 | +700 | 13.03% |
| 4 | 13.2833 | +1228 | +1500 | 16.98% |
| 6 | 48.4127 | +4741 | +6300 | 24.36% |
The house edge column is 1 minus the parlay’s decimal odds divided by the fair decimal odds. A single -110 bet gives up 4.55% on average. A six-leg ticket of the same bets gives up nearly a quarter of every dollar. The payout grows, but the share kept by the house grows faster.
Put another way, three fair coin flips all land 12.50% of the time. A three-leg parlay at -110 per leg needs to land 14.37% of the time just to break even. The gap between those two figures is the margin, and no choice of legs makes it disappear unless the individual prices are better than fair. The no vig calculator shows the fair price for each leg if you want to check that, and the parlay calculator shows how far the combined ticket sits from it.
Building a live parlay in-play
A live parlay works the same way, with two differences. The prices come from in-play markets, which usually carry a wider margin than pregame lines, and they move between plays.
Here is a live example built at halftime of an NBA night. Leg one is a moneyline at -120 (1.8333), leg two a second-half total at +110 (2.10), and leg three a moneyline in a later game at -140 (1.7143). The product is 1.8333 × 2.10 × 1.7143 = 6.60, so a $10.00 stake returns $66.00, a profit of $56.00, or +560 in American terms.
The live parlay locks its price at the moment the sportsbook accepts it. If a leg’s price changes during the bet delay, the book may reject the slip or offer it at the new combined price, so read the accepted odds before assuming the payout. Live legs are also suspended often, especially in football after each snap, which means a slip with several in-play legs can be hard to place as built.
One more wrinkle catches people out. A live parlay built early in a game often includes a leg whose price already reflects the score, such as a moneyline on a team leading by ten at -400. That leg barely moves the payout (1.25 in decimal) while adding its own margin and a real chance of a late collapse. Short legs are cheap to add and expensive to lose.
Mixing a live leg with pregame legs is common and changes nothing in the math. The calculator does not need to know which legs are live. It needs their prices at the moment of acceptance.
Same game parlay: what the calculator cannot price
A same game parlay combines several bets from one game, and that breaks the assumption behind the formula. Multiplying the odds only gives the right answer when the legs are independent. In a single game they rarely are.
Take an extreme case. A favorite at -300 on the moneyline (1.3333) and the same favorite at -7 on the spread at -110 (1.9091) multiply to 2.5455, about +155. But a team that wins by more than seven points has, by definition, won the game. The second leg adds almost nothing once the first is known, so the true chance of both hitting sits close to the chance of the spread alone. A book that paid +155 on that combination would be giving money away, and none does.
That is why sportsbooks price a same game parlay with their own correlation models. Positively linked legs, such as a team winning and its quarterback throwing for a lot of yards, are priced shorter than the product. Negatively linked legs, such as a team winning while its opponent’s star scores heavily, can be priced longer. On top of the correlation, these markets usually carry a larger margin than a straight bet, although the exact amount is not published and varies from book to book.
The honest use of the parlay calculator for a same game parlay is a comparison. Enter the legs as if they were independent and note the result. Then look at the price the sportsbook quotes for the same game parlay. The difference is the book’s correlation adjustment plus its extra margin, and you cannot separate the two from outside. If the quoted price is far shorter than the product, the legs are strongly linked, and the ticket is closer to one bet than to three. The same game parlay guide covers how those combinations behave in practice.
When the last leg is still to play
Many parlays end up in the same place: every leg has won except one, and the potential payout is now much larger than the stake. At that point the ticket behaves like a single bet at a long price that has already moved in your favor.
Two numbers decide what to do. The first is the potential payout from this calculator. The second is the price on the other side of the last leg. Feed both into the hedge calculator and it returns the stake that locks in profit whichever way the last leg goes, along with a break-even option that keeps most of the upside.
Some sportsbooks also offer a cash-out on an open parlay. That offer is usually priced below the ticket’s fair value, so compare it with the hedge before accepting it. A $20.00 ticket that now pays $143.18 with one -200 leg left has a fair value of about $95.45 if that last leg’s fair chance is close to two thirds, and any cash-out offer well under that figure is a poor price.