Parlays: The Math Behind the Payout

By 4Football Staff · September 29, 2026 · 10 min read

A parlay ties several bets together and multiplies the payout, but the sportsbook's margin multiplies too. Here is the arithmetic, one leg at a time.

A bettor opens a betting app on a Sunday morning and builds a ticket with five games on it. The stake is $10. The screen says "to win $243." That is a lot of money for ten dollars, and the number is sitting right there in bold type.

Every parlay ticket works this way: a small stake, a large headline payout, and a long chain of things that all have to go right. The headline is real. The chance of collecting it is the part that gets less attention. This guide walks through the arithmetic that produces a parlay payout, shows how a sportsbook's margin builds up as legs are added, and covers the rules for pushes, same-game combinations and promotions. It is educational only, with no picks and no encouragement to bet.

Betting on sports is legal only in some places and only for adults of legal age. Prices differ by book and by day, and every figure below is illustrative.

What a parlay is

A parlay is one wager made of two or more separate bets, called legs. The legs can be point spreads, moneylines, totals (over/under) or player props, depending on what the book allows. The ticket pays only if every leg wins. If one leg loses, the entire ticket loses, no matter how many of the other legs won.

In exchange for that all-or-nothing condition, the payout of each leg rolls into the next. The winnings from leg one are not paid out; they are effectively staked on leg two, and so on down the line. That compounding is what produces big numbers from small stakes, and it is also why parlays are hard to win.

The multiplication, step by step

The most reliable way to compute a parlay payout is to convert each leg to decimal odds, multiply them together, and subtract the stake. If you need a refresher on the formats, see our explainer on how betting odds work.

Two conversion rules cover American odds:

1. For positive odds, decimal odds equal 1 plus the odds divided by 100. A leg at +150 becomes 2.50.
2. For negative odds, decimal odds equal 1 plus 100 divided by the absolute value of the odds. A leg at -110 becomes about 1.909.

Decimal odds include your stake. So a $10 bet at 1.909 returns $19.09 if it wins: the $10 you put in plus $9.09 of profit.

A three-leg example

Imagine three spread bets, each priced at the common -110. Each leg has decimal odds of about 1.9091.

1. Leg one alone: 1.9091
2. Legs one and two: 1.9091 × 1.9091 = about 3.645
3. All three legs: 3.645 × 1.9091 = about 6.958

A $10 ticket therefore returns about $69.58 if all three win, which is $59.58 of profit. In American terms that is roughly +596. Notice that the sportsbook did not use a special parlay formula. It simply multiplied.

A mixed ticket

Mixing prices works the same way. Say one leg is -150 (decimal about 1.667), one is +120 (2.20) and one is -110 (about 1.909). Multiply: 1.667 × 2.20 × 1.909 = about 7.00. A $10 ticket returns about $70, a profit of about $60, which a book would display as roughly +600.

What the legs would need to win

The ticket pays one answer for every combination, so the interesting question is how often a ticket like that should win. If you assume the legs are independent (the outcome of one has no effect on the others), the chance of winning every leg is the product of the chances of winning each one.

Say a bettor believes each of three spread bets is a true 50 percent proposition, a coin flip. The chance that all three win is 0.5 × 0.5 × 0.5 = 12.5 percent. That means the ticket should win about once every eight attempts. A fair payout for something that wins one time in eight would be 7 to 1, or +700 (a profit of $70 on a $10 stake). The book above paid +596. The gap is the sportsbook's margin, and it grows with each leg.

How the margin compounds

A single spread bet at -110 on a true coin flip returns, on average, about 95.45 cents for every dollar risked, a shortfall of roughly 4.5 percent. Our guide to the vig explains where that number comes from.

With a parlay, that shortfall is applied on every leg. The average return on a coin-flip parlay at -110 per leg is 0.9545 raised to the power of the number of legs. The table below shows what that does, assuming every leg really is a 50-50 proposition.

Look at the right-hand column. The ticket gets better-looking on the front side, with the payout climbing from +91 to +64,200, and worse on the back side, with the average loss per dollar climbing from about 4.5 percent to about 37 percent. The two things happen together.

That is why a sportsbook is delighted to promote parlays. The headline payout attracts bettors, and the margin on the product is larger than on a single bet. A sportsbook earns more from the same flow of money when bettors choose parlays over straight bets.

Why the table is a fair test and also an unfair one

Any table like this makes assumptions, and good readers know what they are.

• Every leg is a true coin flip. Real spreads and totals are set near the middle of expected outcomes, so for point-spread bets the coin-flip assumption is a reasonable starting point. Moneylines on heavy favorites are not coin flips.
• The legs are independent. For games played by different teams on different fields, that is usually close to true. For legs within the same game it often is not, which is covered below.
• The price is -110 on every leg. Many books use different prices, and a few offer reduced-vig prices that change the outcome of the math.

Change any of them and the numbers shift. The pattern does not. Multiplying prices that each carry a built-in margin always multiplies the margin too.

What if a bettor really does have an edge

Honesty requires the other side of the calculation. Parlay math does not turn a good bet into a bad one; it magnifies whatever is there. Suppose, purely as a thought experiment, that each of three legs at -110 truly wins 55 percent of the time. The chance of winning all three is 0.55 × 0.55 × 0.55 = about 16.6 percent, and the payout of about 6.96 times the stake gives an average return of about 1.158 per dollar, a gain of roughly 16 percent. A real edge is magnified.

Two cautions follow from that. First, a sustained 55 percent hit rate on spread bets is far above what most bettors achieve; the break-even point at -110 is 52.4 percent, and the gap between 52.4 and 55 is large in this market. Second, the same ticket loses 83 times out of 100 even in that favorable case. A series of losing tickets is the normal experience, not a sign something went wrong. Our guides to implied probability and to expected value go into this in more detail.

Why parlays feel so tempting

The appeal is not a mystery.

• Small stakes feel safe. A $5 ticket cannot do much damage, so the decision feels cheap.
• The payout is vivid. A large number on a screen is easy to picture. The 1-in-1,000 chance behind it is not.
• Near misses feel like progress. A four-of-five ticket that loses on a late touchdown stays in memory in a way that a clean loss does not.
• They turn watching into participating. Having a stake in every game on the slate makes the early window more engaging.

None of this is a flaw in the bettor. It is how the product is designed. The danger is that many small tickets add up. Ten $5 parlays a week is $50 a week, and at the average shortfalls above, that stream of money drains steadily. A bettor who notices stress rather than fun can reach the National Problem Gambling Helpline at 1-800-GAMBLER.

The fine print that matters

Pushes

A push occurs when a leg lands exactly on the line, for example a favorite laid 3 points wins by exactly 3. At most books, a pushed leg is removed from the parlay and the ticket is repriced as if it had one fewer leg. A four-leg ticket with one push becomes a three-leg ticket at three-leg odds. Some promotional products and parlay cards treat pushes differently, so check the terms.

A worked version makes the repricing concrete. Say a three-leg ticket at -110 per leg has a $10 stake, and the first leg lands exactly on the number while the other two win. The pushed leg drops out, leaving a two-leg ticket worth 1.9091 × 1.9091 = about 3.645 times the stake, so the ticket returns about $36.45 instead of the $69.58 a clean sweep would have paid. The bettor was one leg away from a bigger payout and still gets a win, just a smaller one.

Postponed or suspended games

Games that are postponed, moved or called off can void a leg, and many books handle that the same way as a push. A game that is only delayed by weather and then completed the same day normally stands. Books publish their own rules on how long a delay can last before a leg is voided, and the rules vary.

Overtime

Overtime scoring counts for spreads, moneylines and totals under the usual rules at most books, so a regulation tie that goes to extra time still settles the leg on the final result. Check your book's terms for any exception.

Same-game parlays

A same-game parlay puts several legs from one game on one ticket, such as a team to win, a quarterback to throw for more than a certain number of yards, and the game to go over the total. These legs are rarely independent. If a team wins by a lot, its running back probably has plenty of carries, and a shootout makes both the over and a passing prop more likely. Sportsbooks know this and price correlated legs accordingly, so the payout is usually lower than the naive multiplication of the individual prices. Some books also restrict which same-game combinations are allowed. The simple model of independent legs is the wrong tool for these tickets, and it can mislead in either direction.

Fixed tables and parlay cards

Some products, including certain parlay cards, pay a fixed table of odds instead of multiplying the individual prices. Fixed tables are often lower than the multiplied number. If a book offers both, the only way to know which one is better is to compute the multiplied version and compare.

Promotions and boosts

Offers such as profit boosts, bonus bets or "insurance" on a leg that loses come with conditions: caps, minimum odds per leg, minimum numbers of legs and time limits. A promotional payout changes the average return, and so the figures in the table above no longer apply. Work out the real payout and what the offer requires.

Mistakes that show up again and again

• Adding legs to chase a bigger payout after a loss. Each extra leg lowers the chance of winning and raises the average shortfall, so the response to a losing week that costs the most is usually the one that feels most natural.
• Treating a favorite's moneyline as a sure leg. A heavy favorite priced at -400 still loses a meaningful share of the time. Its decimal odds of 1.25 barely add to the payout, while its risk of failing is carried by the whole ticket.
• Forgetting that the early game cannot be undone. A ticket that already has three winning legs is still worth nothing if the last game loses, and a cash-out offer on a live ticket carries its own margin.
• Reading a payout without reading the legs. A same-game combination, a boosted leg or a fixed-table card can each explain why a payout differs from the plain multiplication.
• Ignoring the stake in the total. Ten small tickets are ten separate chances for the margin to apply, so a weekly total, not a single ticket, is the number to watch.

Building the numbers yourself

If you ever want to check a payout, you can do it with a calculator in four steps:

1. Convert each leg's American price to decimal odds.
2. Multiply the decimal odds together.
3. Multiply the product by the stake. That is the total return, stake included.
4. Subtract the stake to get the profit, and compare it to the figure on the ticket.

If the ticket pays less than the multiplication, the book has applied correlation pricing, a fixed table or a cap. Knowing which one is part of knowing what you are buying.

Compare that with the parlay's cousin. Our guide to teasers shows how moving the lines changes the same all-or-nothing structure. The current spreads and totals are on the odds page, the results arrive on the scores page, and the schedule shows which games share a kickoff window.

What to remember

• A parlay multiplies the decimal odds of every leg, and every leg must win for the ticket to pay.
• The sportsbook's margin multiplies too, so the average shortfall per dollar staked rises with every leg added.
• On coin-flip legs priced at -110, the average shortfall is about 9 percent at two legs, about 13 percent at three, and over 20 percent at five.
• The chance of winning falls fast: three coin flips win about one time in eight, and ten win about one time in a thousand.
• Pushes usually remove the leg, postponed games usually void it, and same-game legs are priced for correlation.
• Promotions change the math, so recompute the payout using the terms that actually apply.
• Betting is legal only in some places and for adults; help is available at 1-800-GAMBLER.