First and foremost, let me start this article by saying head over to our home page and simplify the tedious calculations using our parlay calculator.

However, if you want to go on the cumbersome journey of crunching your own numbers or you merely want to know exactly how our calculator works behind the scenes, you have come to the right place.

For this example, we will return to our favorite bettor, Joe Schmo.

Joe is a $100 bettor and wants to figure out exactly what the odds would have been on the longshot underdog parlay that could have hit after last weekend’s upsets.

We start by converting the odds into decimal format.

Traditionally odds among all regulated North American sportsbooks are shown in the American format, which looks like this for an underdog +105 and like this for the favorite -110.

It is important to differentiate between these two, as slightly different math applies to converting them to decimal format.

When you are converting a favorites’ odds, those with a – in front of it), you divide 100 by the American odds and add 1.

For example, if you have a favorite at -110, the calculation should be:

**(100 / 110) + 1 = Decimal Odds format**

**(100 / 110) + 1 = 1.9**

When your selected bet is coming in as an underdog, you have to switch the integer. You simply divide the odds by 100 and add 1.

Let’s assume a +105 underdog is on your bet slip.

To convert the American odds:

**(105 / 100) + 1 = Decimal Odds Format**

**(105 / 100) + 1 = 2.05**

Congratulations, you have just successfully converted odds from American into Decimal format.

In our humble opinion, a format that makes betting much easier to understand anyways, but we shall save that discussion for another day.

The next step is to take all the bets on your potential parlay bet slip and convert them.

To keep this explanation simple and short, let’s assume we are doing a two-leg parlay based on the two examples above, one underdog at +105 and one favorite at -110.

But if you were to place a four-leg parlay or six-leg parlay, you would have to do this for all bets before proceeding.

We then multiply the decimal odds of all our bets. In our example above, this would be 1.9×2.05 = 3.895

This number represents the total payout.

All that is left to do is to multiply this number by your bet amount, in Joe Schmo’s case, $100, and you have 3.895 * 100 = $389.50.

This number represents the total payout, including the original money put down for the bet.

If you now want to calculate what the winnings would be, you simply have to subtract Joe’s original bet from the total payout to get $389.5 – $100 = $289.50.

And there you have it; a behind-the-scenes look at our calculator.

## Differences Between Moneyline, Spread, & Over/Under Parlays?

We sometimes get emails that ask us to extend our calculator to include all markets offered.

It is important to note that the parlay calculator works for all bet types independent of which category it falls under.

Let’s run through some examples:

### Moneyline Parlay

For our moneyline parlay, Joe wants to bet three teams.

One of them is at -110 to win, one of them is -160 to win, and the last one is at +105 to win.

As we learned in the steps preceding this section, we first have to convert them to decimal odds:

**(100 / 110) + 1 = 1.9**

**(100 / 160) + 1 = 1.625**

**(105 / 100) + 1 = 2.05**

We multiply all three of these together to get: 1.9 x 1.625 x 2.05 x = 6.33

For a $100 parlay, we would hence win $633 if all of the legs hit.

So, the actual winnings would be $533, after you subtract the original bet amount.

### Spread Parlay

Spread Parlays work very similarly to the moneyline parlay described above.

In this case, Joe wants to place a spread parlay on the NBA. He’s a notorious Raptors fan who are playing against the Cavs tonight. You can find more ideas like this in our free parlay pick of the day.

The big difference between the spread parlay and the moneyline parlay is that we now have two numbers on our bet slip.

The Raptors are -1 against the spread tonight, with the best odds being -110 for them to cover.

For the purpose of calculating our parlay odds, we can ignore the first number and only focus on the odds themselves (-110). Let’s run through an example:

**CLE @ TOR -1 / -110**

**ORL @ MIA -10 / -109**

**CHI @ LAL -1 / -110**

Now we have to translate these into decimal format:

**(100 / 110) + 1 = 1.9**

**(100 / 109) + 1 = 1.92**

**(100 / 110) + 1 = 1.9**

Multiplying all of them together: 1.9 x 1.92 x 1.9 = 6.94

Hence Joe stands to get a payout of $100 x 6.94 = $694 USD if his Parlay was to hit. So his actual profit on the bet would be $694 minus $100 = $594.

### Over/Under Parlay

Lastly, let’s look at the Over/Under and how parlays work here.

Joe Schmo is NBA parlay hungry, and beyond betting on the Spread parlays tonight, he also wants to put some money down on an Over/Under Parlay.

He’s looking to place a four-leg parlay on the following matches:

**ATL @ PHI with the Over/Under being set at 219 / -111**

**MIN @ WAS with the Over/Under being set at 223 / -111**

**CLE @ TOR with the Over/Under coming in at 219 / -125**

**CHA @ BOS with the Over/Under at 227 / -111**

Joe is an avid reader of the BestOdds.com newsletter, so he knows that so far, we have seen quite a lot of unders coming in this season.

Hence, he chooses to bet the under for all four games.

As we know from the section above on Spread Parlays, we can ignore the value that has been set for the Under and just focus on the odds.

Let’s convert them into decimal values:

**(100 / 111) + 1 = 1.9**

**(100 / 111) + 1 = 1.9**

**(100 / 125) + 1 = 1.8**

**(100 / 111) + 1 = 1.9**

To get the payout for this four-leg Parlay, we now multiply all of them together: 1.9 x 1.9 x 1.8 x 1.9 = 12.35.

If we now multiply this with Joe’s $100 he put down, we get $100 x 12.35 = $1,235 if the Parlay hits.

So a tidy potential profit of $1,235 minus $100 = $1,135.

## Differences In Parlay Bets Between Sports

The math we have outlined above works for all bet types and sports.

Whether you’re placing a bet on College Basketball, College Football, Tennis, or the NHL, as long as you get the odds, you can convert them and calculate the parlay odds.

You can also add as many legs to the Parlay as you want. The most common types of parlays are 3-leg, 4-leg, 6-leg, or 10-leg parlays.

Some books will limit you on the exact number of max legs which is normally around 15.

To find out more about which books are best to place parlays, make sure to check out our Parlay Sportsbook Guide.

There is only one potential exception, which is same-game parlays. Let’s dive into those briefly.

**Calculating Same-Game Parlay Payouts**

Same-Game Parlays have become increasingly popular recently.

They are exactly what they sound like: You combine multiple bets about one single game into one Parlay.

For example, you combine a moneyline wager with a player prop and a team prop. In theory, the math should work exactly like in regular multi-game parlays.

However, there are two special considerations:

Some books will not allow you to combine all types of wagers into a single game parlay.

Often, sportsbooks will restrict you when you’re trying to parlay the most likely touchdown scorer in an NFL game with a Moneyline bet on the favorite.

The probability of this happening is simply too big. Most books simply don’t have the risk appetite for it.

The other instance to watch out for occurs when bettors attempt to bet on highly correlated markets.

For example, if Joe Schmo wants to bet the Over and combine this with the Quarterback in an NFL game to go above his prop for Passing Yards.

This is a bet that is likely correlated. As such, the book will either not want to accept this bet, or they will apply a discount in the odds to reflect that if one occurs, the other event is also very likely.

Unfortunately, there is no exact formula to calculate the fair odds for correlated same-game parlays, as different books have different internal policies for how to price this type of risk.

**Push In Parlay Bets**

Let’s assume Joe has placed a bet on the over for tonight’s Nets game, with the Over/Under set at 217.

The game ends, and the final score happens to be exactly 217.

This bet was the final leg in his four-leg parlay, with all other bets hitting. Does that mean his Parlay is lost now?

Luckily for Joe, his Parlay is still alive and well. If a push occurs in one of the parlay’s legs, it is simply removed from the Parlay.

That means if one of the four legs in Joe’s Parlay is a push, but all others hit, his payout will be recalculated to include all legs but the one that had the push.

Let’s run through a brief math example for this. Here is Joe’s five leg parlay:

**Vikings ML @ -110**

**Raptors Spread -1 @ -115**

**Geno Smith Over 23.5 Completions @ -110**

**Nets under 217 @ -110**

If all four legs hit, the payout would be:

**(100 / 110) + 1 = 1.9**

**(100 / 115) + 1 = 1.87**

**(100 / 110) + 1 = 1.9**

**(100 / 110) + 1 = 1.9**

1.9 x 1.87 x 1.9 x 1.9 = 12.83 / $100 x 12.83 = $1.283

Now, as outlined above, three of the four legs have hit, and his last one resulted in a push.

Hence, the payout from his Parlay is now:

1.9 x 1.87 x 1.9 = 6.75 / $100 x 6.75 = $675

## Converting Odds Into Implied Probabilities

Once you have determined the payout and odds for your Parlay, you might wonder: How likely is it that this Parlay will hit?

Let’s take the example from Joe Schmo above with his four-leg parlay:

**Vikings ML @ -110 (Decimal: 1.9)**

**Raptors Spread -1 @ -115 (Decimal: 1.87)**

**Geno Smith Over 23.5 Completions @ -110 (Decimal: 1.9)**

**Nets under 217 @ -110 (Decimal: 1.9)**

The payout for this Parlay for a $100 bet would be 12.83 x $100 = $1.283.

As we have established in the earlier sections of this article, this payout includes the original $100 bet, so to proceed, we have to subtract it.

The net winnings of Joe’s Parlay without the $100 would hence be $1.238 – $100 = $1.138.

The next step is to understand what our actual odds of winning are. To do this, we have to divide the net winnings by the original wager. In this case:

$1.138 / $100 = 11.38.

To proceed, we need to convert these odds back into the American format.

We can do this manually using this formula: (Decimal Odds -1) x 100 = American Odds; Or you can use our odds converter on BestOdds.com.

For Joe’s Parlay, the American odds would be: (11.38 – 1) x 100 = 1038 or +1038 in the language of the book.

The formula we have applied here only applies when your decimal odds are above 2.

If they are below 2, you need to use the following formula:

**-100 / (Decimal odds -1) = American Odds**

It is relevant to note here that it’s highly unlikely for a Parlay to be below 2.

This usually only applies when you are trying to convert single markets to American odds from Decimal odds.

You have almost made it to the end; there is all but one final formula to apply.

To get from our American odds to the final probability, we have to apply the following calculation:

**100 / (American Odds + 100) x 100 = Probability**

Using our Parlay odds from above, we would hence get:

**100 / (1038 + 100) x 100 = 8.787%**

Hence, the sportsbook believes Joe has got an 8.787% chance of hitting this Parlay.

If you are a sophisticated bettor who creates your own odds, you can use these formulas to compare your estimated probabilities to the books.

If you believe you have an edge on the book and find probability differences between you and the book, you might have identified value.

But let us emphasize once more that betting, and especially parlays, should be considered a form of entertainment for most and if you can take advantage of various parlay bonuses to limit spending your own money.

Be responsible, and have fun but keep yourselves in check.