Moneyline Odds to Probability Converter

For anyone new to Moneyline odds, it can be difficult to get your head round what the odds mean in terms of the probability of the event happening. Since ‘Moneyline’ odds (also known as ‘American odds’) are very commonly used across sportsbooks in the US, they can act as a barrier to entry for anyone wanting to put some bets on.

In particular, matched betting is a great side hustle that’s suitable for people who have never gambled, or have no interest in sports. Whilst you don’t need to understand the sports themselves, you will need to understand how odds work.

Our calculator will convert Moneyline odds to probability, so you can quickly understand how Moneyline odds work. Simply enter your odds below, and we’ll calculate the probability of that event occuring.

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How Moneyline Odds Work

Put simply, Moneyline is a way to wager money on a specific event happening, such as a team winning a game. The value of the odds provide a way to calculate your return on a bet, should that bet win.

There are three scenarios that could occur when you place a bet:

  • Bet Wins – Your selected team won and you'll receive your stake (bet) back plus your winnings.
  • Bet Loses – Your selected team lost and the sportsbook keeps your stake.
  • Draw – In the event of a tie, the bet is considered void and your stake is returned to you.

Moneyline odds operate between -9999 and -100, then +100 to +9999.

A negative moneyline represents the favorite for an event. The value itself represents the amount of money you'd have to stake to win $100.

A positive moneyline represents the underdog. The value represents the amount of money you would win if you stake $100 and the underdog prevails.

Converting 'American' Odds to Percentages

Converting Moneyline odds to percentages can be a bit tricky, as you need a slightly different formula depending on whether you have a negative or positive moneyline.

Converting a Negative Moneyline to a Probability

You need to take the presented odds, and divide them by the odds + 100. Multiplying your result by 100 gives you a percentage.

(odds /(odds + 100)) * 100

For example, if we have a Moneyline of -400, we would have the following calculation:

(400 /(400 + 100)) * 100

=(400 /(500)) * 100

=(0.8) * 100

=80%

You can check that by using our calculator above.

Converting a Positive Moneyline to a Probability

You need to take the presented odds, add 100 and then use the resulting number to be the denominator under 100. Multiplying your result by 100 gives you a percentage.

(100 / (odds + 100)) * 100

For example, if we have a Moneyline of +400, we would have the following calculation:

(100 /(400 + 100)) * 100

=(100 /(500)) * 100

=(0.2) * 100

=20%

Again, you can check that by using our calculator. You'll notice that -400 (80%) and +400 (20%) result in covering 100% probability. They are the only two results that could possibly occur.

What is Implied Probability?

You'll notice that we use the term Implied Probability in the calculator, simply because we don't know what the true possibility of an event happening is. That's for a couple of reasons:

  • Imperfect Information - We don't know every possible factor that goes into calculating the percentage of an event happening. That's easy on a 50/50 coin flip, but very hard for example when there are 53 players on a roster, each with different fitness concerns, playing styles, and tactics. We can only guess what the true probability of a team winning is.
  • Sportsbook Odds - When a sportsbook presents odds to us, they are factoring in a range of different inputs. Those include how much risk they are exposed to for an event happening, where they might want to incentivize betting on the opposite event, as well as their 'vigorish' (commission).

So, we now understand that moneyline odds can't be trusted to represent an exact value of the probability of an event happening. Therefore, we use the term 'Implied Probability' as the odds do imply that the event has a certain chance of happening.

Most professional gamblers are looking for a mismatch between the true odds they believe, and the odds the sportsbook are offering. As matched bettors, we are simply looking for dutching opportunities with two moneyline odds that are as close as possible.

Services like ProfitDuel provide automated systems to find the odds that will make us the most profit when matched betting.

About The Author

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David has been matched betting for over 10 years, with experience profiting from bonus bets in the UK and Australia. He's made over $30,000 from just a couple of hours each week and funded travel across the world. He struggles to understand why matched betting isn't more popular when it's the perfect side hustle.

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