Online Betting » Betting Guide » What are American Odds and How Do They Work? Exploring US Odds

What are American Odds and How Do They Work? Exploring US Odds

Dave Kuzio
Fact checked by: Jim Knight
Publish Date: 01.07.2024

You will never be successful in betting unless you fully understand the different types of odds that are on offer.

Yes, you can alter your settings in your relevant betting accounts to have your preferred odds format displayed, but it does not hurt to be clued up in how the others work.

American odds can be quite tricky to master, so I have prepared this guide to help you understand the mechanics of American odds and how they actually work.

What Are American Odds?

There are three main odds formats that are used in sports betting. Decimal, fraction and American odds. American odds are mainly used in America – shock I know – but some UK punters like to use this format when it comes to the NFL, NBA, Boxing or UFC.

The best way to understand American odds is that they tell you how much you can win when you bet £/$100 or how much you require to bet in order to win the same amount.

American odds have a positive and negative number in front of the figures to determine who is the favourite and who is the underdog. If the soccer game you are backing has one team at -200, then they are the clear favourites. If you back the team at +250 then they are the clear underdogs.

I need to be clear here. You do not always have to bet £/$100. This is just a simple guide to follow. You can always use an online calculator to work out how much you will receive on any staked amount.

How Do American Odds Payouts Work?

The payout in American odds betting will vary depending on the odds you receive – just like any betting format. Once you have placed your bet, that price is locked on and will not change for you.

Here is a brief overlook on the payouts you would receive when you back the favourite and the underdog:

Negative Odds

A bet with negative odds means you are backing the favourite and that number is what you need to stake in order to win £/$100.

  • Odds -200: Bet £/$200 to win £/$100

Positive Odds

Placing a bet with positive odds means you are backing the underdog and the number you see is what you will receive if you stake £/$100.

  • Odds +250: Bet £100 to win £/$250

The examples I have used so far in the American odds betting guide have been on the money line market. Below I will explain the different markets that are available:

Money Line

The money line market is very easy to understand. Basically you are just backing which team you want to win in a certain game. The side with the negative odds will be the favourite and the team with the positive odds are the underdog.

New York Jets +260

Cleveland Browns -320


Spread betting is also popular – especially in the NFL. It can also be used during soccer matches as well. You are not betting on one side to actually win, you are predicting the range of the final score. It is very similar to handicap betting.

Using the NFL as an example here, if you think that the Washington Commanders will win a narrow match against the New York Jets then it would make sense to do a spread. The Commanders are priced at -110 for +3 points while the Jets are the same price for -3.00. It is important to note that not all bets will have a positive and negative. Sometimes both teams will have a negative number, it is always best to check all the odds before placing your bet.

  • Washington Commanders +3 points -110
  • New York Jets -3 points -110
  • Arizona Cardinals +4.5 -110
  • Chicago Bears -4.5 -110


The over and under market is popular in a wide range of professional sports. Once again, the NFL leads the way in terms of over/under being very popular. In simple terms, you are backing on the amount of points being scored in any given game. You will choose your figure and then decide whether or not the points scored with his over or under that specific score. In American odds betting you might come across the term ‘push’. This confirms that the bet is tied or void when the punter or bookmaker fails to win.

Cowboys @ Dolphins51.00-11051.00-110
Packers @ Panthers36.5-11036.5-110
Saints @ Rams44.5-11044.5-110

How To Convert American Odds To Fractional & Decimal Odds

American odds are easy to understand once you get the hang of them, but they are not everyone’s cup of tea. Whether you use American, fractional or decimal odds, it’s all about personal preference.

Even if you favour one over the other two, it won’t cause any harm if you are clued up on all three formats.

Here is a brief explanation on how to convert American odds so you can understand them as fractions or decimals:

Convert To Fractional

I have explained in more detail about fractional odds in this article, so I will just briefly explain the formula needed to convert from American to fractional.

For positive odds, you will need to divide the American odds by 100 and then reduce the fraction to its lowest possible.

  • Odds 140
  • 140/100 = 14/10 = 7/5

For negative odds, you will be dividing by -100. The formula will be -100/AMerican odds = fractional odds.

  • Odds -160
  • -100/-160 = 0.63 = 6/10 = 3/5

Convert To Decimal

To convert positive American odds to decimal odds, you need to divide the money line by 100 and add 1. For negative odds, you need to divide 100 by the US odds and then add the value to 1.00.

  • Decimal odds = (US Odds/100) + 1
  • US Odds +200
  • (200/100) + 1 = 2+1 = 3.00
  • Decimal odds = (100/US Odds) +1
  • US Odds -130
  • (100/130) + 1 = 0.769 +1 – 1.769

Calculate The Probability Of US Betting Odds

Without confusing you too much, working out the probability is done with another formula. You can just use an online calculator if maths is not your strongest subject, but it is good to know how everything works.

You will be well aware now that American betting odds use positive and negative numbers.

For the negative odds, you will use the following formula:

Odds/(Odds + 100) x 100 = Implied probability

  • Odds -140
  • 140/(140 + 100) x 100 = 58.33%

For the positive odds, you will use the following formula:

100/(Odds + 100) x 100 = Implied probability

  • Odds +120
  • 100/(120 + 100) x 100 = 45.45%

American Odds Pros And Cons

  • Easy to understand favourite and underdog
  • Clear instructions on how to calculate winnings
  • Confusing to understand at first

Final Say On American Odds

If you are a regular at betting on American sports like NFL and NBA, then this format is ideal for you. Once you have mastered the whole positive and negative equations, then you should be able to decipher your bets very quickly.

Being English I am more comfortable using the fraction system. It was something taught to me in school, so I have always stuck with that method. Not everyone is like me, a lot of people like the American odds way of betting.

It is a very cool system once you understand it. It pays to take time to study each betting market and get a handle on what you are betting on. Once you have done that, using American betting odds will not be too alien for you.

American Odds FAQ

🇺🇸 What Are American Betting Odds?

American betting odds is one of three methods used in sports betting. American odds use positive and negative figures to determine the favourite and underdog. 

🤷 Do You Have To Use American Odds?

No, it is all about your preferred choice. Each betting website that you use will have an option in your account to allow you to change to the format you want. That could be American odds, fractional or decimal.. 

👁️‍🗨️ Is It Difficult To Read American Odds?

At first, I would  say it is a little confusing, especially if you are used to using fractional or decimal odds. Just remember if a number has a negative symbol in front of it then that is the favourite. A number with a plus symbol in front is the underdog.

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