How to Read Betting Odds

If you’re new to the world of sports betting, one of the first things you’ll need to do is figure out how betting odds work. At a quick glance, betting odds can be quite intimidating to first-time bettors, and you may find yourself asking “how do betting odds work?” That’s where can help; we’ve taken it back to the basics to explain betting odds and how they work.

Odds Converter


What are betting odds?

The first step to understanding betting odds is appreciating what they do. Betting odds simply indicate the likelihood of an event and the return you’d get if you did make a wager on the result. Betting odds may be displayed in three different formats at US sportsbooks and online and mobile sports betting platforms: American odds, fractional odds and decimal odds. Different formats don’t mean different odds; it’s simply a different way of presenting them. This isn’t as complicated as it might sound and, by the time you’ve read our guide to betting odds, you’ll be an expert.

American odds

You’re most likely to come across American odds when you’re betting at American sports betting sites. This odds expression indicates a bettor’s return relative to a base figure of 100 units. American odds start with either a positive or negative sign (e.g. -200 or +200).  A minus sign indicates a bookie’s favorite to win while a plus symbol indicates an underdog. A -250 favorite has a better chance of winning an event than a -150 favorite, while a +200 underdog has a better chance of winning than a +500 underdog.

Let’s consider a real-world example to understand how American odds work in action:

In an NFL game between the Chargers and the Patriots, a sportsbook sets odds of +170 for the Chargers to win. This means a $100 bet would net you $270 if they did win- that’s a profit of $170. However, if you were to make a successful bet on the Patriots winning, at odds of -190,  your $100 would see a return of $152.65- a more modest, $52.65 profit.

When it comes to calculating the return from a bet made using American odds there are two different formulas that can be used:

  •    Calculating negative odds: (100/Odds) x Stake = Profit
  •     Using the example above: (100/190) x $100 = $52.65
  •    Calculating positive odds: Odds x (Stake/100) = Profit
  •    Using the example above: 170 x ($100/100) = $170

When looking at American odds, it’s important to remember that the results of some matches have a points spread attached to them. This applies to a variety of sports including NBA, NHL, NFL and MLB games.

When a point spread is attached to a set of odds it means that for the bet to be successful the team must ‘cover the spread’. This means that the team you are betting on must win or not lose by a predetermined margin of points.

For example, the Chargers could have odds of (+4) -110 to win. The (+4) indicates the point spread, meaning the Chargers would need to win by 4 points for the bet to be successful. This shows that, even though a team may be a sportsbook’s favorite, the final score must cover the point spread for a bet to be successful.

Fractional odds

Displaying odds in a fractional format is more common in overseas markets, such as the UK, than at US online sportsbooks, but it’s useful to understand them nonetheless. Fractional odds are some of the most simple to understand, as they present your potential winnings as a fraction of the money you stake: while the denominator represents the amount bet, the numerator is the amount your stake will yield in a winning bet.

For example, odds of 1/1 mean you’d get a return of $20 for a winning $10 bet. Want a real-life example? Making a $10 winning bet on an NBA game priced at 5/1, would net you $60 in total.

You can use the following formula to calculate potential returns with fractional odds:

  •  ((Stake/ denominator) x numerator) + stake = return
  •  For example: (10 x 5) + 10 = 60

Decimal odds

The decimal odds format, also known as European odds, represents the multiple of your stake that you will get back for winning a bet. While these are more common at overseas betting exchanges, you may see these at US betting sites. For example, betting on a market priced at 2.5 means you would win two and a half times your stake if your bet were to win. This means you’d win $2.50 for every $1 you wager.

Another example of decimal odds in action would be betting on NHL game with odds of 9.0. A $10 stake on odds of 9.0 would earn a total payout of $90 with $80 being won from the sportsbook and your initial $10 stake being returned.

You can use the following formula to calculate potential returns with decimal odds:

  •    Calculating total payout: Odds x Stake = total payout e.g. 9.0 x $10 = $90
  •    To calculate profit: (Odds x Stake) – Stake = profit   e.g. (9.0 x $10) – $10 =$80

Comparing different types of odds

Whichever format odds are written in, they all have an equivalent in another format. While some sites, such as William Hill’s Jersey sportsbook, allow bettors to change odds formats, it is useful to understand how to calculate odds between formats. Not only will this help you understand your potential return, but it also makes it easier to compare betting odds across sportsbooks.

Fractional odds to:

Decimal American
(numerator/denominator) + 1 = decimal odds Convert fraction to decimal x 100 =American odds
(11/4) + 1 = 3.75 (11/4) x 100 = 2.75 x 100 = 275

Decimal odds to:

Fractional American
(decimal odds-1) and round to nearest integer =  fractional odds (decimal – 1) x 100 = American odds
(3.75-1=2.75) = 2.75/1 or 11/4 (3.75 – 1) x 100 = 275

Positive American odds to:

Decimal Fractional
(American odds/100) +1 = decimal odds (American odds/100) then reduce to its simplest form
(275/100) + 1 = 3.75 (275/100 = 2.75) = 2.75/1 or 11/4

Negative American odds to:

Decimal Fractional
(100/ American odds) + 1 = decimal odds (100/american odds) then reduce to its simplest form
(100/275) + 1 = 1.36 (100/275 = 0.36) =  4/11

US sports betting markets

We’ve explained betting odds, but what markets are these set on? As the US sports betting industry continues to grow, so does the selection betting options, or betting markets, at each site. Odds will vary between these markets, and even between the same markets at different sports betting sites. Not quite sure what every US sports betting market means? These are the most popular:

Straight bet

A straight bet is a single bet on the outcome of a game or sporting event that is determined by a money line or point spread.


A futures wager is a bet placed on the outcome of an event in the future. For instance, you can place a wager on the winners of the NFL season which doesn’t even begin until next year


A parlay wager is a single bet that is linked with two or more wagers. In order to win a parlay bet, a bettor must win every wager in the parlay. If a bettor loses one wager in the parlay then they will lose the entire parlay bet. Parlay bets tend to have much higher odds than other bet types.


Teaser bets are usually available for basketball and football events. A teaser allows bettors to combine their bets on two different games and adjust the point spreads for the two games. However, the better will see a lower return in the event that their teams win.

Round robin

A round robin is essentially a series of parlay bets. For instance, a round robin made up of three teams will consist of three two-team parlay bets.


Propositions bets are sometimes referred to as “prop” bets. These bets focus more on the outcome of a certain event happening during a sports game such as “which team will score the first touchdown?” or “how many field goals will team x score?”

It’s up to you to compare betting odds and pick your betting market. If you’re new to sports betting, we’d recommend sticking to ‘safer’ bets with lower odds until you get to grips with how it works exactly.

While gambling odds can vary between US sports betting sites, you should now be equipped with the knowledge and know how to start betting and find the best odds on the US sports betting market. Not sure where to bet? US has the latest on the best legal sportsbooks in your state.

The people behind this page's online gambling content experts helped write, edit and check the content on this page:

Jake is a gambling content specialist for, with a focus on the regulated US market. He is responsible for producing news content for News, state guides for US and has interviewed several senior executives within the gambling industry. Jake previously wrote for Gambling Insider and LGBT+ news site PinkNews.