How to Read Sports Betting Odds at Online Sportsbooks

Understanding sports betting lines and odds is crucial to being able to place bets, particularly those that win and bring in exciting payouts. Betting lines allow you to see the odds for a particular wager, while the odds signify which team is more likely to win and how much you can earn from a successful bet on one of the two competing teams.

If you want to know more about how to read sports odds and betting lines, then you’ve come to the right place. This guide covers everything you need to know, from odds formats and the different betting markets to details on why betting lines move and what this means.

What Are Betting Odds?

Sports betting odds and betting lines go hand-in-hand. But before we can look at betting lines, it is essential to understand what betting odds are and how they work since the odds often influence the lines provided by a sportsbook.

Odds provide two sets of information for a bettor. Firstly, they highlight how likely a team or athlete is to win the sports match they are playing in. This tells the bettors whether a bet on that team is more likely to win or lose them money.

Sports betting odds also reveal to a bettor how much they can win off a bet placed on a particular team and how much they will need to put down to win back a specific value, should the team they are backing be successful.

How Do Betting Odds Work?

Betting odds are relatively straightforward to understand. A sportsbook, through several avenues, will set its odds and release them to the bettors. Bettors then review these odds to see which team is more likely to win and the payouts they can earn on a winning bet. Then, they place bets on their favorite teams. Before the sports match begins, the sportsbooks close the betting lines and no longer accept any further wagers. Bettors who win their wagers are then paid out according to the odds offered by the sportsbook.

Calculating Betting Odds

Sports betting sites devise their own betting odds based on research and information gleaned from various databases. These sites analyze the details, stats, and information on each team and player to assess the probability of the various outcomes and then set the odds accordingly. Sportbooks then also apply their commission or Vigorish to the odds. This is the amount of money the sportsbook makes as a profit for offering the bet, and it is how they make their money.

In many cases, online sportsbooks will also refer to Vegas odds or the sports betting odds outlined by sportsbooks located in Nevada, Las Vegas. Bookies often turn to Vegas odds as this is where gambling began, making it the capital of gambling know-how in the country. Here, sports betting sites will find the best, most accurate, and up-to-date odds on a range of sports, making it easy to align their offerings with the best.

Once a betting site has settled on its odds and applied its vig, they post them on their websites for sports bettors to use.

Unibet PA Betting Lines and Odds

Calculating Payouts from Sports Betting Odds

Odds indicate how much a bettor can earn off a winning wager. There are a few ways bettors can use the odds to calculate how much profit they can earn from a bet they place.

  • Betting Calculator: Bettors can search online for a betting calculator, which will help them determine possible payouts dependent on how much they wager on a particular market. This offers an excellent way to see which odds are worth the risk and what value wagers are more likely to be profitable and worthwhile based on your bankroll.
  • Betting Slip: When you select your sports betting line at an online sportsbook, this information appears on your betting slip. Besides these details, you will also see your potential payout.
  • Estimate It: There are two rules of thumb that allow you to create an estimate quickly on the fly:

If you have negative odds, the number indicates how much you will need to put down to win back $100. So, for example, if the odds are -120, you will need to wager $120 to win back $100 in profits. When you win your bet, you receive your original stake back as well as the profits you have won. So, in this case you will receive a $220 payout – your $120 original stake and $100 in profits.

Conversely, if the odds are positive, the number highlights how much you will win as a return on a bet of $100. So, for instance, if the odds are +155 and you wagered $100, you would win a profit of $155, making your total payout $255 ($100 original stake + $155 profit)

However, these rules typically apply to American odds. Below, we take a closer look at the various betting odds formats you can find at the best online sportsbooks.

Sports Odds Explained: American Odds

The top online sports betting apps and websites provide odds in several formats. While some sites offer fractional or decimal odds for some sports like horse racing, online sportsbooks in the US typically offer American odds as the default format.

American odds display as three figures preceded by a plus (+) or minus (-) sign. The positive or negative values help bettors determine which team or athlete participating in a sports match is most likely to win. The figures that follow indicate for the bettor how much their potential payout will be.

The negative odds highlight the favorite or the team or athlete set by the sportsbook as the most likely to win the game. Then, the numbers that follow the minus sign show a bettor how much they will need to put down on a bet to win back $100 in profits. For example, if the Philadelphia Eagles had odds of -135, they would be the favorites for that game. Additionally, bettors will need to wager $135 on the team to win back $100 in profits if the team wins the game, leaving them with a total payout of $235.

Conversely, the team with the positive odds is the underdog or the team or athlete least likely to win the game. The numbers behind the plus sign indicate how much a bettor will win in profits off of a $100 wager if that team is successful and wins. For example, if the Kansas City Chiefs had odds of +180, they are the underdogs. And, if a bettor wagered $100 on them and they won, the bettor would earn $180 in profits, making their total payout $280.

Handy Hint:

Because there is more risk in betting on the underdog, the odds for that team or athlete are typically higher. This is why you need to pay in more to win $100 on the favorite and why you only need to wager $100 on the underdog to win a greater payout.

Unibet PA NFL Preseason American Odds

Calculating Winnings with American Odds

While you can use a betting slip, an odds calculator, or an estimate, it also helps to know what equation you can use to determine the exact possible payout on a wager you place. Since not every bettor will wager precisely $100 or so on a bet, understanding how to calculate a potential payout using American odds is handy. So, let’s look:

Say, for example, you placed a $40 bet on the Philadelphia Eagles at odds of -130.

Here, your equation would look like this:

130⁄100 = 40⁄𝑥

Then, you would cross multiply to solve for x: so, 130x = 4,000

Which means x = 4000 ÷ 130

So, x = 30.77

In this case, if you wagered $40 on the Eagles at the given odds of -130 and they won, you would win $30.77 in profit, making your total payout $70.77 (initial stake $40 + $30.77 profit)

But what if you bet on positive odds?

Say, for instance, you wagered $40 on the Kansas City Chiefs with odds set at +110. In this case, your equation would look like this:

100⁄110 = 40⁄𝑥

Then, you would cross multiply to solve for x: so, 100x = 4,400

Which means x = 4400 ÷ 100

So, x = 44

Here, if you wagered $40 on the Chiefs and won, your profit would be greater than your wager because the odds are higher. So, you would earn $44 in profit plus your original stake of $40, leaving your total payout at $84.

Calculating Implied Probability with American Odds

While betting odds allow bettors to see how much they can earn off a winning bet, they also enable bettors to calculate implied probability. Implied probability outlines the likelihood of a particular outcome. By looking at this value, bettors can see how likely it is for their bet to be a winning wager and calculate whether the risk is worthwhile. To determine implied probability, bettors must convert the betting odds into a percentage.

Although this seems like a lot of work, this calculation can help you see whether it is worth placing a specific bet and whether what you have worked out differs from that of the sportsbook. If it does differ, you may want to adjust your wager.

For instance, if you thought that a team had a 70% chance of winning and the sportsbook offered it at 62.4% implied probability, this would be a good bet.

However, keep in mind that a sportsbook adds its commission or “vig” to its odds as well. As a result of this, your calculated implied probability percentage will be higher than 100%. As a result, it is essential to remove the added vigorish to get a more accurate depiction of what the sportsbook predicts the outcome will be.

Working out implied probability can be challenging, but the formula is relatively straightforward:

Risk/Return = Implied Probability

So, let’s see what this looks like in practice using American odds.

Use this Formula with Positive Odds

Since positive odds are more easy to calculate, we will begin with these. The equation when working out the implied probability for the underdog reads as follows:

IMPLIED PROBABILITY = 100 ⁄ positive odds +100

So if we were to use our previous example of the Kansas City Chiefs with odds of +110, the equation would read:

100 ⁄ (110 +100)

= 100 ÷ 210

= 0,476 or 47.6%

In this case, the implied probability of the Chiefs winning the game is 47.6% according to the sportsbook. Since this value is close to 50%, if you think they have greater chances of winning because of the weather or some other factor, we recommend considering wagering on the team.

How Do Negative Odds Differ?

The equation for negative odds differs slightly from the one we have just gone through, and this is because we need to flip the negative values to positives, which requires a little more work. Additionally, this equation cannot be used for positive odds. As a result, the formula for the favorites reads as follows:

IMPLIED PROBABILITY = negative odds ⁄ negative odds +100

So, let’s use our earlier example of the Philadelphia Eagles, with odds of -130. Here, our equation would read:

(- [-130]) / (- [-130] + 100)

= 130 / 230

=0.565 or 56.5%

Here, the Eagles have a 56.5% chance of winning the game according to the sportsbook, making them the better option to go with for this match.

Decimal Odds Explained

One of the three most common formats for an online sportsbook to display its odds is in decimal odds format. Decimal odds are the easiest to work with, making calculating payouts and implied probability much simpler. Decimal odds look and read like a decimal number. Here, the decimal number highlights how much a bettor will win for every $1 they wager.

As a result, bettors can determine the underdog from the favorite instantly, just by looking at the number value. The team with the lower decimal value is the favorite as their odds are lower. Conversely, the underdogs are the team with the higher decimal value.

Unibet PA NFL Preseason Decimal Odds

How Do You Understand Betting Odds With Decimal Odds?

American odds highlight the profit a bettor can make (not including their original stake). In contrast, decimal odds represent a bettor’s total payout from a winning wager. This makes it much easier to calculate your winnings.

For example, say there was a game between the Philadelphia Phillies and the New York Mets. If, in this instance, the sportsbook set the betting odds at Phillies (1.66) vs. Mets (2.28) and you bet on the Phillies, the equation would look like this:


So, if you were to bet $50 on the Phillies here with odds of 1.66, your equation would be:

(50 x 1.66) – 50

= 83 – 50

= $33 in profits

Since the $83 would be your total payout including your original stake, you need to minus your original wager value to see how much you would win in profits off the bet.

This equation is used for both the underdog and favorite’s odds to determine winnings.

Implied probability is also much simpler to work out for decimal odds since there are no positive or negative odds. Here, all you need to do is divide one by the odds and then multiply that value by 100 to get the percentage:

(1 ÷ decimal odds) x 100 = IMPLIED PROBABILITY

Again, this equation can be used for both the underdog and the favorite.

Sports Odds Explained: Fractional Odds

Another of the more frequently offered sports betting odds formats is fractional odds. Here, the sportsbooks display the odds as a fraction. These are most commonly found in UK sportsbooks or racebooks covering horse racing.

An example of fractional odds could be 9/5. These are read aloud as nine to five.

How Do You Understand Odds in Sports Betting With Fractional Odds?

Reading and understanding fractional odds is relatively straightforward. If we use our example of 9/5, the number on the left (9) outlines how many times the sportsbook expects the relevant outcome to fail. In contrast, the right-hand side number (5) shows how many times the sportsbook expects the outcome to be successful.

Typically in fractional odds, the favorite will have a denominator (bottom number) bigger than the numerator (top or first number). For example, the favorite may have fractional odds of 5/9 or 1/2.

In contrast, the underdog will have a numerator bigger than the denominator, for instance, 9/5 or 2/1.

Unibet PA NFL Preseason Fractional Odds

Fractional Odds in Action

In addition to horse racing, fractional odds are commonly used for sports like boxing, so let’s use a boxing reference here as an example. Say the sportsbook gives Nathaniel Collins odds of 8/13 in his fight with Raza Hamza. These betting odds indicate that if the fight took place 21 times (we get this value by adding the two odds values together – 8+13), Collins would lose eight times, but he would win 13, making him the favorite.

Calculating Implied Probability

To work out the implied probability of Collins winning the boxing match we divide the number of times he is predicted to win and divide it by the total number of fights:

Denominator ÷ (Numerator + Denominator) = Implied Probability

So, using our example, the equation would read:

13 ÷ (8+13) = 61.9%

Bettors can use this same formula to calculate the implied probability for both the favorite and the underdog. It is only for American odds where there are negative numbers that there are two separate equations.

However, it is important to remember that sportsbooks apply vigorish to their sports betting odds no matter which format they display them in. If Collins’ opponent, Raza Hamza had odds of 11/8, using the equation above we would determine that his probability of winning is 42.1%.

To work out the vigorish applied by the sportsbook you can add together the implied probability percentages of both teams or athletes. In this case, 61,9% + 42.1% = 104%

Since the value here is over 100% you can see that the bookie has added their juice (another of the sports betting terms used to describe vigorish) of 4%.

Calculating Your Winnings Using Fractional Odds

Working out your potential winnings using fractional odds is relatively simple, as it is for decimal odds. The formula you would use to work out your potential payout is as follows:

Fractional Odds Winnings = Wager × (Numerator ÷ Denominator)

Using our example for the boxer Collins, with odds of 8/13, say you wager a $20 bet. Your equation would look like this:

20 x (8÷13)

= 20 x 0.615

= $12.30

Your total payout would then be your profit ($12.30) plus your original stake ($20) leaving you with a total of $32.30.

What are Lines in Betting?

A sports betting line is the gambling odds a sportsbook sets for a specific type of bet on a particular match for both the underdog and the favorite. These betting odds create a line or margin between the opposing teams or athletes, setting the parameters for bets on the game.

Bettors read the sports betting lines to determine the odds offered for a particular type of bet and decide on which team to back.

How do you Read a Sports Betting Line?

Now that we understand how to read sports odds and how they work, it becomes easier to read a betting line. Betting lines show the odds for both the underdog and the favorite for a specific type of wager.

A betting line will show both teams or athletes participating in a game along with their odds for that particular game.

The betting odds for the two teams or athletes may differ according to the different types of bets a  bettor can wager on the team. Additionally, a betting line may offer additional information alongside the sports betting odds, like points spreads or over/under values.

Below, we take a closer look at the different betting lines offered and how to read them.

How To Read Moneyline Odds

The most straightforward sports betting line is moneyline odds. Here, bettors make a simple bet by putting money on the team they predict will win the game. Since the wager is straight up, a sportsbook will offer odds for the favorite and the underdog. If we look at American odds, the favorite will have a negative value next to it, and the underdog will have a positive value.

If we look at our example below, the Phillies are the favorites with odds of -140. Here, a bettor backing the Phillies must wager $140 to win back $100 in profits. Conversely, the Rockies are the underdogs, and bettors wagering $100 will win $115 in profits if they back the Rockies and they win.

Team Moneyline Odds
Colorado Rockies +115
Philadelphia Phillies -140

It is also important to note that in some sports, like soccer betting, there are three-way moneyline odds. Here, bettors are given three sets of betting odds which they can choose from, since many soccer matches often end in a draw. Here, the bettor can pick the underdog or the favorite to win or they can predict the game will end in a draw. These betting lines look like this:

Team Three-Way Moneyline Odds
COL Crew -103
FC Cincinnati +250
Draw +265

Here, you can see there is more of a likelihood of COL Crew winning the match than FC Cincinnati or the game ending in a draw.

Unibet PA Soccer Three Way Moneyline Wager

Spread Betting Odds – How To Read Point Spread Bets

Another common wager bettors place when betting on the Super Bowl or the NBA or even on sports like hockey or baseball is the point spread. The point spread offers bettors another way to wager on the final outcome of a game. In this case, the sportsbook applies or removes points from one or both teams creating a handicap that levels the playing field and improves the odds. Here, the bettor places their bet based on whether their chosen team will cover the spread.

For instance, using the example below, the sportsbook has applied a 4.5 spread or handicap. Here, the Eagles are the favorites with a -4.5 point spread. For a bettor backing this team to win their bet the Eagles must win by more points than set out by the spread (cover the spread), in this case, they must win by five points or more.

In contrast, the Jaguars are the underdogs with a spread of +4.5. Bettors backing the underdog will only win if that team wins outright or if they loose by fewer points than outlined in the spread. So, if you backed the Jaguars and they win outright or lose by four points or less, your bet wins.

Team Point Spread Odds
Philadelphia Eagles – 4.5   -110
Jacksonville Jaguars + 4.5   -110

But, looking at the odds here, both teams have odds of -110. This is because the applied spread has evened out the chances. Here, the Jaguars have just as much chance of losing by less than four points as the Eagles have of winning by five points or more. In this instance, irrespective of which team you choose to back, you will need to put down $110 to win back $100 in profit.

Handy Hint:

Many online sportsbooks apply a half point or “Hook” to their point spread odds. They do this to prevent the bet resulting in a push. A push is when one of the teams doesn’t cover the spread but lands exactly on the number of points outlined by the sportsbook. When this happens the sportsbook must refund bettors their original stake. So, to prevent this the bookies add a half point, so there is a definite value that must be met in order for the wager to be a winning bet. For instance, in the example we used above, the sportsbook has added a hook, leaving the spread at 4.5 instead of at 4.0.

Futures Betting Odds

These betting lines are much what they sound like, wagers that bettors can place on things yet to take place or that will happen in the future. Here, bettors can wager on things like the outcome of a sports tournament like who will win the MLB. Sportsbooks release their betting odds for futures bets during the off season. Then, once the tournament gets underway, they adjust the odds according to how the tournament progresses.

However, it is important to note that futures bets are very tricky to get right and the odds are displayed a little differently than most. So, let’s look at our example below to get a better idea.

Team MLB Championship Winner Futures Odds
Atlanta Braves +325
Los Angeles Dodgers +450
Houston Astros +650
Texas Rangers +750
Tampa Bay Rays +850
Baltimore Orioles +950
Philadelphia Phillies +1800
Toronto Blue Jays +2000

If we look at the above example, bettors here must pick a team they predict will win the MLB championship. In an instance where there is a negative value, the team with the negative  number furthest away from zero is the favorite.

However, if we look at the example above, all the teams have positive odds. This is typical for futures bets since the bettor must pick a winner before the tournament has even begun, the betting odds are always higher. In this case, the team with the sports betting odds the closest to 100 is the favorite. Here, that would be the Atlanta Braves with odds of +325. The greater the number becomes, the less chance the sportsbook thinks that team has of winning, so in this case, the Toronto Blue Jays with odds of +2000 are the underdogs.

Unibet PA Soccer World Cup Futures Betting Lines

Golf, Tennis, and Event-based Sports

Some sports like golf or tennis offer unique betting lines and odds. For example, those wagering on golf will have betting lines that allow them to back the player they predict will be the outright winner of the tournament which reads more like a futures bet but works like a moneyline. Additionally, golf bettors have the option to back the players they think will finish in the top 5, 10, 15, or 20 positions, which allows them to pick that number of players depending on their odds.

However, those who enjoy tennis betting may find unique betting lines like set betting. Here, they can wager on which player will win a particular set, instead of the overall game.

Other sports like mixed martial arts allow bettors to place wagers like Method of Victory (how a UFC bettor will win their fight) or rounds betting, which in UFC betting allows a bettor to predict which round the fight will end on. If bettors can accurately predict this, their bet wins.

Those learning how to bet on horses will also find that in horse racing betting, there are unique betting lines like exactas, trifectas, superfectas, parlays, and picks.

Unibet PA Tennis Set Betting Lines

Odds and Line Movement

Betting odds movement refers to a shift in the betting lines posted by a sportsbook for a particular wager, team, or athlete. For instance, if a sportsbook releases sports betting odds for the favorite in an NFL game at -110 and multiple bettors then back that team, the odds may shift to -120.

It is essential to remember that betting lines may see movement between the time the sportsbook posts the odds and when they close the line for betting before the game begins. It is essential to watch line movement as, in many cases, line movement can lead to less favorable odds. If you see this happening, you may want to quickly browse other sportsbooks to find the original odds you had your sights on, as these will soon move too. Once there is line movement at one sportsbook, the others generally follow soon after.

Why Do Sports Betting Lines Move?

There are several reasons why betting lines move. However, they all have to do with the odds. Generally, lines see movement when there is a flurry of bets placed on a particular team in a sports match. For instance, sharps or pro bettors may find excellent odds on the favorite and quickly place several bets on this line. The sportsbook will pick upon this movement and shift the line so as not to have to pay out as much to other bettors who follow suit.

Another cause of lines shifting is the betting public or everyday recreational bettors. Generally, these bettors back the favorite or the home team as these are often quick and easy ways to secure a winning bet. This heavy activity on the favorite or home team causes the odds to shift. However, in this case, the odds are often not a true reflection of what the outcome may be, and here pro bettors will typically back the underdog or bet against the public.

Are Betting Lines The Same At All Sportsbooks?

Sportsbooks can and do set their own betting odds. However, many of these sites offer similar odds based on research and Vegas odds. As a result, the variation in betting odds offered from one sportsbook to another varies ever so slightly. But it is still worthwhile shopping around to find the best odds. While this may not make a huge difference for smaller wagers, those placing higher stake bets will find this affects their payouts significantly on a winning bet.


What sportsbook has the best odds?

Can you lose money on a winning bet?

What happens if you bet on negative odds?

What do odds mean in betting?

What are lines in betting?

Why would you bet on negative odds?

How do you choose the best bets?

What is a fixed odds bet?

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