Parlay Betting – What It Is & How It Works

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Mike Epifani, Author

Last Updated : 01/27/2025

Parlays are among the most popular forms of sports betting. It’s a high-risk, high-reward practice that pays out well when it hits but can drain a bankroll due to its high variance. New to parlay betting? Here’s what it is and how it works in the simplest terms.

Brand new? Here’s how to bet on sports.

What Is Parlay Betting?

Parlay betting is when you combine multiple bets (called “legs”) into one wager to increase the overall payout. This also increases the risk because all legs need to be correct for the parlay to win. At sportsbooks, bettors can select the different bets, and the sportsbook will automatically give them the option to combine them into a parlay or place them as separate bets.

Bettors in almost all US states can place parlays. Here’s which states offer online sportsbooks.

The Math Behind Parlay Betting

The math behind parlay betting is simple. The final odds are simply each individual wager multiplied together. However, the odds are multiplied in the “decimal odds” format (e.g., 1.5, 2.5, 3.2) versus the American odds format (e.g., -110, +100, +250).

To calculate parlay odds manually, you’d need to convert American odds into decimal odds, multiply them together, then convert the final decimal odds back to American odds. Thankfully, the sportsbook does this for you automatically, and there are tons of online parlay calculators out there.

But here’s a breakdown of how the math works anyway.

Converting American Odds to Decimal Odds

The formula for converting positive American odds to decimal odds is:

  • 1 + (American Odds/100) = Decimal Odds
  • Example for +100 odds: 1 + (100/100) = 1 + 1 = 2
  • Example for +250 odds: 1 + (250/100) = 1 + 2.5 = 3.5

The formula for converting negative American odds to decimal odds is:

  • 1 + (100/American Odds) = Decimal Odds
  • Example for -110 odds: 1 + (100/110) = 1 + 0.909 = 1.909
  • Example for -500 odds: 1 + (100/500) = 1 + 0.2 = 1.2

Calculating Parlay Odds

Once you have the decimal odds for each leg of the parlay, multiply those numbers together to get the final odds. For example:

  • +100 = 2.0
  • +250 = 3.5
  • -110 = 1.909
  • -500 = 1.20

Then multiply the decimal points together: 2.0 x 3.5 x 1.909 x 1.20 = 16.0356.

You can multiply that final number by the wager to see the total payout for the bet. So, if you were to bet $100 on the example above and all four legs are correct, you would win $1,603.56.

Converting Decimal Odds Back to American Odds

If you want to see the final odds in American odds, use these formulas:

Decimal Odds Greater Than 2.0

  • (Decimal Odds – 1) x 100 = American Odds
  • Example for 2.5 Odds: (2.5 – 1) x 100 = 150

Decimal Odds Less Than 2.0

  • 100/(Decimal Odds – 1) = Negative American Odds
  • Example of 1.5 odds: 100/(1.5-1) = -200

Decimal Odds Exactly 2.0

  • 2.0 decimal odds is even money, which is +100 in American odds.

For example, if the final parlay odds are again 16.0356, the calculation would be:

  • (16.0356 – 1) x 100 = +1503.56, which would be rounded up to +1504.

But, again, the sportsbook will do all that math for you. You can also find a bunch of parlay calculators around the web.

Types of Parlay Bets

Multi-Game Parlays

Multi-game parlays are when you combine multiple games from the same sport into a single wager. The most popular versions of this are betting on NFL Sunday games and Saturday college football games. Multi-game parlays were the first parlays introduced and continue to be the most popular.

Multi-Sport Parlays

A multi-sport parlay is the same principle as a multi-game parlay except with more than one sport. For example, you might combine the winner of an NFL game, NBA game, and college football game into a single wager. Multi-sport parlays allow bettors to spread their wagers to several events they feel confident about rather than being limited to one sport.

Same-Game Parlays

A same-game parlay combines bets related to a single event, such as points spread, totals, and prop bets. If all the legs hit by the conclusion of the game, the parlay pays out. In fact, if you parlay prop bets, it’s possible for the wager to pay out before the conclusion of the game.

In some cases, you can also place a same-game parlay while live betting. This is most common at real-money sportsbooks, but some social sportsbooks offer this feature on select sports as well.

Same-Game Plus Parlays

Same-game plus parlays are when you combine a same-game parlay with any other wagers. For example, you might place two separate same-game parlays, then combine them both into one single parlay. You might also combine a same-game parlay with straight bets on different games.

Final Thoughts on Parlay Betting

Parlays are an exciting and potentially lucrative form of sports betting, but they come with significant risks. While the allure of big payouts is tempting, remember that every leg added to a parlay reduces the chances of winning. Be strategic with your parlays, use them sparingly, and always gamble responsibly!

Read More: Parlays Vs. Single Bets